End of Portal 2 got me choked up, surprisingly. Laughter and a few wistful tears.
Hrm, what else?
Oh yes!
Ending of Starcraft, (not expansion.) The way the final battle worked out made it such a huge, epic fight, and then seeing the self-sacrifice of Tassadar, with the music and everything was badass and tearful.
Ending of the first Lufia game, so bitter-sweet, with the possibility of a happy ending.
Ahh Lufia, the only JRPG I ever played from start to finish.
Those are the ones I can remember while straining. I tear up more at books, movies and, (once,) with tv.