We've featured a few DIY laptop trays before, but if your laptop is prone to overheating, this DIY rack (custom-built to fit your computer) should keep it cool with a few USB powered fans.
The above video shows a cheap, simple way to turn an old binder into a more advanced laptop cooling tray. If you've been building computers for a while, you probably already have a few fans lying around, and this will cost you next to nothing to build. Plus, what's great about it, is that if you have a small netbook (like the Eee PC in the video), you can build the stand to fit your computer perfectly, instead of waiting for some manufacturer to do it for you. Check out the video to see it in action, and while you're at it, give your laptop a good clean to make sure it stays cool. Also, hit the link at MakeUseOf below to see a ton of other great DIY laptop cooling solutions.