I try not to do it TOO much for fear of losing myself in a myriad of different personas that I have to portray. Each tabletop, or larp, or MUSH character is a little part of myself, and I can't spread that self too thin.
But anyway, on to the real subject of this post.
Game this weekend. Wow... That's really all there was to say about it. mr_sarcasm is probably one of the most talented GM's I've ever met. He ranks right up there with my uber roomie silas7, who wrote a Vampire chronical that survived a two year story without need for reboot. We came to 'endgame' this weekend for the story we were on, and it rocked. I'll linked to his post about it for the nitty gritty details, the thing I wanted to pontificate on was when the first NPC death happened.
Once the 'storytelling' of the scene had been completed, mr_sarcasm gave us some RP time and went out for a smoke (dirty habit). Every one of us just sat there in stunned silence for a good two minutes. It was obvious that players and characters alike were dumbfounded. We all knew, going in, that something like this could happen, but the reality of it was still couched in 'game'. When it finally happened, the wall between game and reality sort of fell down, and we all felt it as our characters did.
It was totally intense.