A steamboat seems like a good place to start!
Honestly though I started something else today. It was an 'Innitiative Stone' despencer. I'm going for the primative look, making it from a dead Aspen Tree limb, a scrap piece of decking I tore out last summer and an ostrich paper mashe egg from Hobby Lobby. It works! , well sort of, sometimes it doesn't spit out a stone, other times it spits out two, and in random directions.
I'm concidering enslaving a gerbal to run on a treadmill (you know the wheel contraption that goes round and round) to operate the mechanism through a set of home made gears and pegs. Perhaps I'll just hang a fake mouse from the wheel and motorize it. Naturally I'll hide the motor and batteries and put the switch in a discrete place.
It will probably just sit on the workbench for a while perhaps indefinately.
Yea, a Twilight theamed steam launch seems much easier. The last one only took me a few hours.