Labs are awful, aren't they? Here are a couple of thigns that I have done:
In labs where you don't have to work in groups, get permission to wear noise-cancelling headphones and play some sort of white noise on an ipod or Cd player.
I have also gotten by in group-work labs by doing the work as best I can with my group, and then waiting until almost everyone else has finished and left the room to do the individual written part (works when the lab is supposed to be entirely an in-class activity).
I would be very interested to hear what others do for coping strategies, since sometimes, of course, you just can't escape... 