Painkiller.
It probably won't be your thing, since it eschews a plot and ADS aiming for shooting at things until the Havok engine takes over, but if you need some stress relief, I can't think of many better games for that purpose. Also, it has a lot of very awesome weapons. (Ever wanted a gun that fired shurikens and lightning? Or a shotgun with a built-in freeze ray?)
It probably won't be your thing, since it eschews a plot and ADS aiming for shooting at things until the Havok engine takes over, but if you need some stress relief, I can't think of many better games for that purpose. Also, it has a lot of very awesome weapons. (Ever wanted a gun that fired shurikens and lightning? Or a shotgun with a built-in freeze ray?)