One of my online chess games. A pretty even game all the way until it ended with a colossal mistake, as chess games sometimes do. Some annotations below . . .
5. b3 Rubinstein Opening
37. Qf1 I kind of wonder about this move as it lets Black deliver a queen check on the 2nd rank.
39. Nf6+?? We were both running short of time (in a 2+1 bullet game) and I was about to offer a draw when White did this, missing that he can’t recapture.
40. Qfx6+?? So he recaptures anyway.