i've had a few random "shoot me in the dark with your uzi" moments.
my best would be Battlefield 2, got to love that t90 shooting down attack choppers
. RTCW: Enemy territory, to rush the enemy right away and plant some explosives
. System shock 2 also, the respawning hybrids or toxic spiders while taking your time modifying a gun that has bad blocks and get utterly surprised
my best buy by far was the old x wing fighter, which has probably the same dynamics and physics freespace does when i bought that about 5 years later. that x-wing game was a dos game and was neatly built.
i was surprised by one game though, forsaken. that was a lot of fun when you had that titan and trojacs on board.