While at DevTeach, a colleague was struggling with a laptop that was flaky because it was running hot. He had it on an exhibitor's table, which was cloth-covered, and the soft surface was impeding the vents, which were mostly on the bottom. I passed along this tip to him, and I just heard that it worked as well for him as it has for me, so I thought I'd share it more widely.
Take three or four pens, the same size as each other, and lay them parallel on the desk or table like this: I I I I
Then carefully put the laptop down onto the pens. If you only had one it would wobble, if you only had two it would roll around, but three or four are pretty stable. Presto, your cooling is dramatically improved and your laptop stops being quite so flaky. I've even presented like this, for one of those talks with two VPCs that really pushes your CPU hard.