Just last night, I had a dream where I was Jack from BioShock, and I was in the medical pavilion in Rapture. I was low on ammo and Eve for my plasmids, and there were Splicers running towards me from all sides. Then suddenly, I got a weird impulse to say, "Activate VATS!" Then everything froze, and I found that I could use the VATS targeting system from Fallout 3 to target their individual limbs. Since they were all generic Thuggish Splicers, I used this to cripple them and get away to stock up on resources. Then I woke up.
This most bizarre part of this dream wasn't the BioShock/Fallout combination, but the fact that I haven't played either of those games for a while. I guess this dream could have happened due to my excitement for BioShock 2 coming out in February. The only thing that would have made this dream better is if I was a Big Daddy instead of a common man.