I am officially addicted to (fluff)Friends - a facebook application which allows you to adopt a virtual pet and interact with other pet owners from the whole world - actually that was old news - I have been an addict since last year. So there's nothing new.
I've just recently had a crazy idea to start a virtual (fluff) company - a company that is only valid and recognised in the (fluff) world. So far none has existed yet - yes you have virtual companies where no offices are needed but this is redefining the meaning of virtual company as it only is defined by the (fluff) community.
For more information on fluff - http://www.fluff-friends.com/
You need to login to facebook.com to enjoy full access to fluff, though.
Update: As at end 2011, the developer of (fluff)Friends has decided to stop developing/maintaining the app on fb, and has abandoned the app, which has since ceased to function, and has been replaced with iPhone app called (fluff)Friends Rescue.