Me and my friend always play this, we go through a time traveler scenerio and find ways to cause really fucked up and twisted time paradox's, Like I went back in time and kill the inventor of the time machine, making it so I could of never gone back in time and killed the inventor of the time machine, making it so I could go back in time and kill the inventor of the time machine, and so on. It got really fun after a while we made up some really weird shit like going back in time to dinosuar times and bringing dinosuars to the time After the earth was hit so they could continue to live and it ended man kind.  We both still play this from time to time and I was wondering if you guys could come up with some better time paradoxes.