How about a 48 hour hacking session in a house? It forces you to turn of that part of your brain associated with fear of failure, and therefore makes you more creative. Again, this sounds like a cool idea to me.
Let your development team spend a day hacking on a feature they care about. Sounds like a great idea to me. I look around at a lot of the developers I know and they’re running at 50% efficiency because they feel bored doing what the managers say they should the whole time, and the product suffers as a result. Is your company having trouble with staff churn? It’s probably because you don’t let your employees become passionate any more.