My first combat roll! (And my remaining hit points after failing to slay the bugbear).
Though I didn't realize it at first, the adventure we're playing is The Ruins of Undermountain, from the second edition of D&D. I'm a little sentimental about Undermountain because it's the adventure upon which I based the very first D&D campaign I ran as a Dungeon Master. In 1991 I had been playing D&D for about 9 years--since 1982--before I tried my hand at running a campaign. I was a frustrated player at the time, had already nosedived as a DM once, railroading the characters into a planned course of action, and after I'd licked my wounds I was ready to try a dungeon adventure where the choices were a bit more limited. As the players explored Undermountain I became more comfortable with running the game and eventually began to experiment with event-based adventures.
Playing Undermountain 23 years later as my first official post-release D&D experience is really neat. I have only a vague recollection of what rooms looked like, and the dangers that lay nearby.
My first combat roll of (post-release) D&D Next has come after 3 sessions. It was a natural 20 in a gentleman's duel against a bugbear. Unfortunately, that didn't kill the bugbear and its return strike dropped my character, Lord Hubren Delmarek, to -3 hit points. Lesson learned: don't duel bugbears at level 2.
I've been playing crazy with the dice so far. Rolled my character with a straight 3d6 per score. Rolled my hit points at 2nd level instead of taking the average. I also found a Wand of Wonder (suitably fitting) and when the party was in danger I pointed it at the twisted reflections of ourselves emerging from the hall of mirrors and just happened to roll a fireball, blasting them to smithereens.