I agree with what's been said.
I have 3 laptops folding in the office as most of the time they're just sitting idle.
First thing I noticed is they're damn fast, I don't know why but they are. They are all PIII 1Ghz (I haven't looked at the other H/W) doing 5.5 points (not Gromacs) in an 9 hour day (I can't leave them on 24/7).
The fan was on constantly and they were getting a bit warm so I dropped the CPU percentage to 80% which has made them much better. I've also put little pads under the feet to improve airflow.
Something that happened before I started folding is that a laptop got the blue screen of death and went un-noticed for a few hours. When I found it it had practically melted, I guess the heat control had stopped. If you're going to leave a laptop unattended, make sure it's running a nice stable OS.
If anyone's interested, the laptops are on a network in the office and I didn't want them to fold when they were out of the office ie, on battery power and without internet connection. So I installed EMIII running in invisible mode which runs the console across the network at startup. If the laptop is out of the office it just fails to load.
I thought about putting 1 in the fridge out of curiosity but decided against it as they're not mine. That reminds me, you can get little 12V fridges for your car, has anyone tried to mod one for their rig?