 Do you know of any time travel combinatorial puzzles?
weaksauce: I don't know if it is exactly what you are looking for but here is a game that came up a while ago on HN where you need to go back in time and have your robots do things to allow the other robots to make it to the door:
http://news.ycombinator.com/item?id=244594Pretty fun game for a little diversion though it gets old after the 3rd teeter-totter level.