Stumbled across couchdb thanks to the Sakai devel mailing list.  Looks cool, but I need to use it before I can get my head around what it might be able to do.  I think a good toy application that will also be useful is to code up Mike’s glossary using it.  That would be good because the limitation of a wiki is that when you want to add links to existing pages, you have to guess or whatnot, and anyway a wiki is not a glossary.  I just want a dynamic, editable, cross-linked glossary.  That isn’t hand-generated!