I thought up a few Altcoins when I was half asleep the other day, let's see if I can remember them:
CacheCashA cannon is built in a locality. GPS caches are fired from the cannon. Inside the cache, when found (as difficulty increases, indicators on website become more and more vague), an RFID tag will hold a 1024-bit redemption code which, when entered, finds a block.
FitcoinProof of work is based on measurement your movement during the day. To get more money, you get fitter.
LagCoinProof of work is based on the amount of time it takes your computer to connect to a server. As difficulty increases, it will need longer and longer ping times to successfully find a block. Try GPUing that
MetaCoinProof of work involves buying and selling MetaCoin. Hard to get this one started!