I'm going to giving an old imac g3 (one of the huge colorful TV looking things) to a neighbor kid for kwanzukahramadasoltimas, but I want to put some kind of Linux in it. Can anybody recommend a distro that will work well with a g3 imac? Will Ubuntu ppc actually run on w
a g3 ppc. 333 mhz?

I found a website with PPC Distros. I'm not entirely sure if they'll work with your iMac, but you can try :]

http://penguinppc.org/about/distributions.php