The only direct contribution I've made to Ubuntu so far is
http://www.kde-look.org/content/show.php?content=23171
which is simply a slight modification of a kubuntu grub bootscreen.

I hope to contribute a lot more in the future.

I'm also DAXELROD on the CPAN: http://search.cpan.org/~daxelrod/ , although some of my software there is currently out of date and will also be updated.