Give yourself permission to just "piddle around." Clean and organize your room, read the QB, troll the Internet, just do what you want! When I've lost my ambition it helps that I don't put pressure on myself to get back at it; we do this for fun don't we? When I get an inkling that I want to create something, I pick something small and quick like a little quilted coin purse or a tabletopper. I often just pick a block from quilters cache that I have never done before and make it. This way, I try out a new block and it keeps me from being committed to a project that I most likely wont complete. I just pick one that has an interesting name.
http://quilterscache.com/