Currently, the new Mirror's Edge game. I finally beat it, but that was only after I realized how stressed and angry the side challenges were making me and thus gave up on them. I mean, there is ZERO room for error on even the simplest speed trials. I was missing things by a good fifteen seconds in some cases, and it was torture. So finally, I just said, "Screw it," and completed the story to get the game out of my system. I mean, I wasn't expecting a perfect ranking on everything, but I like to think I was good enough to at least finish in the maximum allowed time limit, but no.
Honorable mention: the new Resident Evil Beginning Hour trailer. Granted, it was almost midnight and I had work in the morning, but just walking through the house was starting to get my heart pounding. I picked up the bolt cutters (or was it a wrench?) and went upstairs before I just couldn't take it anymore. So yeah, I didn't even get to any part where anything shows up. I was just too stressed.
Going to give it another go though, once I'm not half asleep.