Is it possible to put a ps3 and and xbox 360 open them both and put them in a computer gaming case

I guess so. The ps3 and xbox 360 are just basically a simple motherboard with a processor with hard drive storage and outputs. My only concerns would be how to join the two motherboards (without damage), combatibility issues, and overheating. In addition, there is a very high chance of data corruption. Simply, just don't try it!