The new ArtCal uses feeds from Flickr, blip.tv, and also searches for links back to each listing via Bloglines Citations. When you're out taking photos and videos, or writing about shows, don't forget to tag/link appropriately.

This page (which was used for the screencap above) shows a good example of all three.

Update: Here is another idea for artists and galleries. If you have video or computer animation in a show, and your website isn't really set up well for video (unlike this), put some excerpts on blip.tv and tag them so that people visiting the exhibition page on ArtCal can watch them.