Not exactly from a game, per se. In my city, there's this 'space-camp' esque place that's basically a very well-crafted computer and video aided LARP-ing center with a Star Trek theme (they've got fully constructed sets for ships, you're given a position on the ship and you have a computer screen through which you carry out your duties, I always picked engineer). Anyways, the mission we were running was called Bug Hunt. We were the clean-up crew for some sort of Federation experiment they wanted to keep hush-hush.
So, after discovering that the things we were supposed to find were some sort of genetically-engineered super-mutants that had phaser-resitant hides, we find the derelict where we're supposed to encounter them. We scan it, no life-signs. Our tactical officer prepares to open fire and remove the evidence when the 'abandoned' ship opens fire on us, tearing a hole in our oxygen generators (the Federation scientist on board kindly neglected to mention his creations are sensor-invisible). I try desperately to fix it, but we're missing an integral part. With only ten minutes of oxygen, we perform a quick sensor sweep. Sure enough, there's a replacement part on the derelict. We have two phasers for our crew of eight, and I have an engineering welder.
The people setting up our mission did an excellent job with the set for the derelict. We 'beam down' from our ship into utter blackness, there are a few flickering lights behind some pitch black curtains, but the visibility is pretty much nothing. We can hear rustling from behind some of the curtains as we clamber over obstacles and crawl underneath what appears to be a chalkboard as we search for the oxygen generator. At last, we find it, bathed in a pillar of blue light. Naturally, we all assume trap. Our two phaser people keep their weapons trained near the light as our first officer reaches for the part, while the unarmed of our crew (including me) prepare to make a dash for it. As our first officer's hand wraps around the part and lifts it up, the 'table' it was resting on jumps up and lets out a blood-curdling shriek (it was one of the places volunteer actors, but hell, she could scream). Naturally, we all run like hell, yelling random profanities and hoping we can get out.
The one moment of almost-hilarity? The first officer (who had since passed off the part and started running) apparently forgot about the chalkboard and hit it face-first running at full speed. He was fine, just a little dazed.