I wrote this little diddy a couple of weeks ago; Since then it has sat on my desktop as a constant reminder of the little time I have to do anything with the snippets of crap that I write on a regular basis.
Due to this very reason, its probably better on the web for anyone who was interested in grabbing colours from Kuler, Adobe labs' user submitted colour... thing.
Usage
require 'kuler'
include Kuler
Kuler::recent
=> ["0E2F32", "C1E6B7", "006A69", "AAC593", "236555"]
This will give you an Array of recently posted colours' in hex values, other options are Kuler::rating and Kuler::popular
Having a poke around the Kuler site should show you that no decent API exits, however you can send some query strings to their awfully formatted RSS feed.