Inkbunny - Helping furry artists and story-tellers share their work.
Sitecake - Drag and drop CMS for HTML websites. It's flat file CMS so it's pretty fast.
Weasyl - Open-source social art gallery
Textpattern - Textpattern is an elegant content management system that is free, open source software.
Hamail Art Gallery - Hamail Art Gallery is one of the leading art galleries providing an online platform to the creators and skillful people to show their stuff.
TYPO3 - TYPO3.com - Infos, SLAs, Extended Support Versions and more