This is a cool article about removing the built-in infra-red filter from your Digital Rebel camera. People do this so that they can perform astronomy photography, but it usually renders the camera useless for normal daytime photography.
This article explains how to replace the IR filter with a piece of glass, and that you can either use an external IR filter or setup a custom white balance setting to compensate for the lack of the built-in IR filter.
It’s a pretty cool hack and there are lots of photos of the guts of the camera. Also, at the end of the article is a list of good references for hacking the Digital Rebel.
Will I be performing this hack? Not too likely. But it’s cool.