Wikis are everywhere and there is one for everything nowadays. Here are some of my favorites:

Wikipedia – Everybody knows about this website by now. It’s always the first place I check when I want to research/read more info about something. It’s mostly right. :)

WikiTravel – I’ve blogged about this website before but it’s worth mentioning again. Great resource for travelers!

WikiHow – Another one I link to a lot. This pretty much has a howto for everything.

CookbookWiki – everything to do with food and cooking…includes recipes, howtos, and tips

Wikimapia – This is a cool google mashup that lets people make comments about anyplace in the world.

Uncyclopedia – this is the funny/sarcastic version of wikipedia. always good for a laugh.

Lostpedia – must read for lost fans

Mentat Wiki – this one is pretty cool. it has different methods on thinking and gives you tips for studying/memorizing. Great if you’re still in school.