Many years ago, during a game my players decided to push their luck in combat. All five of them needed less than 200-300 xp to level up, so they were taking some serious risks, especially because the didn't know that more enemies were coming. They were going to die instead of level up.
On a whim, I told everyone to against their lowest ability score. When several of them made a successful roll, I declared they leveled up and they gained their hp and new abilities on the spot. Their reaction was amazing, after a few swipes with better odds, they retreated to take stock.
Never did it again. What I did to keep the suspense going was to keep a running tab of their experience points and when I handed out EXP, I only gave them combat experience totals. If they gain roleplaying EXP I kept it to myself and would drop it on them, usually in the middle of a dramatic moment during the session. "Hey! You leveled up!" I never invoked the die roll thing again.
I don't like taking things from players, but sometimes a little mystery is good. What do you think?
