Happens to my roommate as well, but that's because his Mobo is very close to being fried....
anyway, trying to isolate factors here. Any hardware patterns? You all using Nvidia cards? Amd processors? etc etc? (I'm more of a hardware fellow)
On the subject of the crashes are there any other programs running into issues when it happens? (Connectivity issue?)
Run your task manager in the background and watch your RAM use when/if it happens again (Memory leak?)
make sure you take a gander here and read through to make sure everything's up to snuff as far as updates. There are a lot more things to update than a lot of people realize.
(I have no idea how tech savvy you are, so apologies if this is all very basic or super-complicated to you)