I thought of this neat little game. Basically, you take the timeline before you, add some jump in time or something, and put it there. Then you post it. Then the next person takes it and adds on more, ad infinium. Use MS Paint. Oh, and provide a description of what happened.
Person A travels back in time a tiny bit and steals the old time machine and the new one, preventing himself from changing the timeline.Person A travels back and creates a alternate universe with his knowledge
Person A travels into future