I'm going to do this day by day, and I don't have answers to all the questions, so I'll take a leaf from Dyson and do mine all at once.
1: First person who introduced you to D&D? Which edition? Your first Character?
Greg Novak, school librarian and history teacher at the rural high school + junior high that I attended from grades 7 to 12 found me reading my SPI catalog in the library, confronted me thinking I had swiped his from his office. On learning I was a fellow subscriber, he started introducing me to a wider range of wargames, by hauling me down to Champaign Urbana for miniatures game nights at the Knights of Pythias Hall. One of the earliest of those was a mega Chainmail game on the huge green carpet, with about 20 people. I ran a small command of Robin Hood and Sheriff of Nottingham 1/72 Airfix guys and was hooked for life. A year or two later, winter of '74 or '75, at the Winter War convention held by that group, I think it was Gary Gygax at the Tactical Studies Rules table in the little dealer's room, down from Lake Geneva selling these little brown boxes that were a big expansion on the fantasy rules at the back of Chainmail that I loved so much, so I had to get it. D&D and Seastrike! which I think Herb Barents was selling were my big buys for the con. I may be getting two successive cons mixed up in my head, since I remember them being in different rooms, so either they had to split the dealers to two smallish rooms or it was different years.
2: First person YOU introduced to D&D? Which edition? THEIR first character?
My mother was the first victim of my dungeon mastering as I was sorting out how to run brown box D&D. I do not at all remember the character. She played once, liked it okay, but wasn't a gamer, just humoring me and finding out what this thing I was so obsessed with was.
3: First dungeon you explored as a PC or ran as a DM.
Shortly after that trial run with Mom, I started drawing a megadungeon on a huge sheet of ten to the inch Lockheed graph paper that my dad had brought back from an Air Force TDY. I inflicted it on my HS wargaming friends and we were all hooked pretty instantly. I looked at the Outdoor Survival map, wasn't thrilled with it, so the outdoors map I started with around that dungeon was a repurposed SPI tactical wargame map from a game I didn't like. It had a lot of levels to squint at and went much deeper than was ever explored. Eventually some bad DM calls I made on some of the vague parts of the rules led the game to spiral out of control and require a reboot with saner interpretations, on a new campaign map of a fantasy continent with many smaller dungeons.
4: First dragon you slew (or some other powerful monster).
The first memorable one was a giant (maybe two?) that our 1st and 2nd level party beat with archery and crossbows and really lucky dice.
5: First character to go from 1st level to 20th level (or highest possible level in a given edition).
Never have. I spent way more time on the DM side of the table, and bounced around in different games as a player.
Probably whatever was first in a pile of characters when Russell Cluver was learning to DM with me as his solo player target. He was more a wargamer than a DM, so I spent an evening or two with a succession of first level characters dying grisly deaths in his dungeon. It was like hardcore mode in an action computer RPG but slower and with dice. We were both wargamers, getting into D&D, so I wasn't too invested in any of those characters.
7: First D&D Product you ever bought. Do you still have it?
Brown box D&D, unless you count the copy of Chainmail that preceded it. The box disintegrated to loving abuse and backpacking to school day after day, but I still have the tattered, taped booklets.
8: First set of polyhedral dice you owned. Do you still use them?
The original chipping low impact polyhedra mail ordered from Lou Zocchi. I still have some of them, and use them sometimes.
9: First campaign setting (homebrew or published) you played in.
My own homebrew dungeon campaign.
10: First gaming magazine you ever bought (Dragon, Dungeon, White Dwarf, etc.).
Strategy and Tactics #38 CA started my subscription. Might have a couple of AH Generals older than that.
Got Dragon #1 in the conversion of my Strategic Review subscription, and it has my players wanted ad in it.
11: First splatbook you begged your DM to approve.
12: First store where you bought your gaming supplies. Does it still exist?
Slot and Wing Hobbies just outside the north gate of Chanute AFB. Neither that Slot and Wing location nor the air base still exist. But the name lives on, in a succession of locations around the Champaign-Urbana area.
13: First miniature(s) you used for D&D.
I was playing Chainmail with Airfix plastics and Minifigs Lord of the Rings barely recognizable hunks o' lead figures, so I used those. Soon got some McEwan knight for PCs that were multipart so I attached weapons with modelling clay so they could re-equip, and Der Kriegspieler orcs. Lined up a few this afternoon for this cell phone photo. The blob in the middle began life as the place on Russell's painting table where he swiped his enamels painting brush to dump excess paint when painting and before he cleaned it. It grew so big, I asked him to pry it up to use as a dungeon blob. It's a little beat up around the edges but still one of my better oozes.Of course Frodo took a dirt nap when I wasn't looking as I set up this shot. Sigh...
14: Did you meet your significant other while playing D&D? Does he or she still play? (Or just post a randomly generated monster in protest of Valentine's Day).
15: What was the first edition you didn't enjoy. Why?
I used the AD&D monster manual, didn't bother with red or blue box, but was switching to Runequest as my main game by the time the other core books of AD&D came out. Gygax's over-reaction in the Dragon to people actually taking his earlier advice and doing their own thing was part of what soured me on D&D.
16: Do you remember your first edition war? Did you win? ;)
I switched to Runequest. Went back to running a D&D nostalgia game with the original rules around '85 as a 10 year anniversary back to basics thing, but wasn't fighting an edition war. AD&D just wasn't my thing.
17: First time you heard D&D was somehow "evil."
I don't remember exactly. The first DM to really expose me to the more roleplaying characterization as opposed to dungeon tactics and goofiness was doing it the context of leading a church youth so it wasn't a church target initially.
But the Dallas Egbert thing where it really blew up came as I was a high school senior on my way to Michigan State. When I arrived, I got to know a lot of the people involved in that story, via the Tolkien Fellowship and the Barony of Northwoods SCA. Went steam tunnelling with the guy that introduced him to steam tunnelling, knew his chem lab partner and people that had played some D&D with him, learned the unsensationalized version of the story. The flap meant there were black suited FBI agents scrutinizing this "potentially dangerous" subculture of geeky kids chatting and tickle fighting, doing amateur theatrics and singing filksongs at my first Bilbo's Birthday Party as an MSU freshman.
My girlfriend's dorm roommate was a Campus Crusade for Christ member, heavily indoctrinated in the silliness, sure gaming was evil. This roommate freaked out hard at the Cults of Prax Runequest book the GF had, and wanted to burn the RQ stuff. That was probably my first direct confrontation.
18: First gaming convention you ever attended.
Strangely enough it was right next door to my house. Greg Novak got use of the Loda Grade School for the prototype Winter War convention, in '73 I think. Our horse pasture was all that was between my house and the school. Mark Miller was there, hawking Fire in the East and some of the first copies of Triplanetary. I got one of those, in which he'd inked in the colors on the planets by hand.
20: First non-D&D RPG you played.
Probably GDW's En Garde in playtest sessions in the "History Club" Greg Novak hosted after school on Wednesdays. I ran some Empire of the Petal Throne and Traveller when they came out, and tried Tunnels and Trolls but didn't like it much.
Dumped my copy of the Palace of the Vampire Queen scenario in a family auction sale as I was thinning down stuff for a move. I didn't like it, so it seemed to make sense, but kicked myself afterwards when it started to skyrocket in value as a collector's item.
I was too old for the D&D novels, and was already well steeped in the full Appendix N palette of sci fi and fantasy of the 70s and earlier. Read one or two that I don't remember the titles to and stopped.
A D&D filk song to the tune of the Green Berets.
What bits I can remember...
"One hundred men will die today, only orcs will walk away."
"Fireballs are hard to fight, for they make heat and lots of light."
"If you should meet an evil MU, kill him first or he'll kill you."
24: First movie that comes to mind that you associate with D&D. Why?
Ralph Bakshi's "Wizards" and "Monty Python and the Holy Grail" both came out while I was playing D&D and heavily influenced me.
D&D - probably my 80s nostalgia game, though fewer sessions over a longer time than my original 70s game. Group? I still play assorted games with some of the same people I've been playing with most Saturday nights for over two decades. The group has morphed over time as some people left gaming, moved away. One died in an accident.
26: Do you still game with the people who introduced you to the hobby?
No. My dad, who got me started in my first wargame at age 6 or 7 with a Little Wars like game using the carpet tile squares as spaces, toy soldiers and block forts, died some years ago, and he'd stopped playing AH games while I was still in high school. I moved across the country away from the people I gamed with in my teens. But I am back in Facebook contact with some of my original D&D group.