“You smell that? Do you smell that? Melted computer hardware, son. Nothing else in the world smells like that. I love the smell of burning plastic in the morning.”
As has been my want recently I was using my notebook (a nice new Asus VX1) at the train station on the way to work. When the train arrived I closed the lid, and placed it in the zip-up protective cloth sleeve that it came with, before placing it in my laptop bag. A few hours later I went to retrive it, but I immediately knew there was something wrong. The protective cloth bag was hot on the outside, quite hot and when I un-zipped it there was the smell of melted plastic. The laptop chassis was very hot, too hot to comfortably touch in some places. Some of the keys down one side were slightly warped and it wouldn’t power on. I let it cool down for a while and called the manufacturer. Although it is relatively new (purchased mid-August) they said it would be a case of repairing rather than replacing. This was bad news - I had 3 upcoming WPF presentations later this week and early next week and I’d be without my hardware-accellerated eye candy (and thus might have to deliver some meaningful content instead). Worse was the thought of on-going wrangling with the manufacturer as various components began displaying thermal-induced oddities of behavior. After it had completely cooled down I tried powering it on a few more times, but with no luck. Then (and anyone who is looking for proof that I’m an optimist and not a grumpy b*stard, here it is) I tried plugging the power in, and it booted. Not only did it boot, everything worked perfectly. Wanting to pich myself to prove I wasn’t dreaming I fired up a couple of applications, compiled and ran a few things, all without issue. After running a few Atwood-endorsed hardware tests I was reasonably satisfied everything was OK. Here’s a picture of the slightly warped keys just to prove I’m not making the whole thing up. 
Now I’m left wondering what I should do next (aside from shutting down every time when putting it away)? With the recent spate of battery recalls and house fires being attributed to notebooks you can’t be too careful. A friend suggested I use speedfan to try and ascertain the maximum temperature it reached. I’ll be carefully keeping an eye out for stories of ASUS VX1’s catching on fire, or battery recalls.
My laptop used to have a similar problem; it’d randomly decide to wake up from sleep when it was in the sleeve. Scary stuff, but at least the sleeve is open at the top, so it wasn’t totally baking in there.
Surprisingly, since I did a clean wipe of the machine with Vista, I haven’t had problems with that any more.
Most computer components actually aren’t that heat sensitive. And on a laptop the power supply is outboard anyway (the power brick). What you really have to worry about is the hard drive; the HDD is by far the most likely component to succumb to heat death.
p.s. BoO to case-sensitive CAPTCHA. :P