The first step to playing with interesting scripts is to re-enable non standard transactions on the testnet. I keep meaning to do this but have been busy with other things, like making the testnet-in-a-box.
Making IsStandard() return true if fTestNet is a good idea.The process for getting a new transaction type into bitcoin would be to test it thoroughly on the testnet, get general consensus on its API and/or GUI and that it is useful, safe, and unlikely to be abused, and work with the 'infrastucture' sites (like blockexplorer and bitcoinmonitor) to make sure the right APIs or hooks are in place so they can do something intelligent with the new transactions.