The Paradox of Time Travel

"One stubborn problem with time travel is that it is riddled with several types of paradoxes. For example, there is the paradox of the man with no parents, i.e. what happens when you go back in time and kill your parents before you are born? Question: if your parents died before you were born, then how could you have been born to kill them in the first place?

There is also the paradox of the man with no past. For example, let’s say that a young inventor is trying futilely to build a time machine in his garage. Suddenly, an elderly man appears from nowhere and gives the youth the secret of building a time machine. The young man then becomes enormously rich playing the stock market, race tracks, and sporting events because he knows the future. Then, as an old man, he decides to make his final trip back to the past and give the secret of time travel to his youthful self. Question: where did the idea of the time machine come from?"

-- Dr. Michio Kaku, The Physics of Time Travel

This looks fun... let me try.

There is the paradox of the man with the ambiguous girlfriend. A man "Jack" gets in a fight with his girlfriend "Jane", get's pissed off, builds a time machine and goes back in time before he meets Jane. Then, from the past Jack sends Jane an e-mail saying he's breaking up with her. Jane is confused but highly turned on, since she hasn't gotten any ass in months. Jack and Jane start going out. Question: Should Jack offer to pay the whole bill on the "first date"?

There is the paradox of the man who friended himself on Facebook. A young man in college joins Facebook. He then receives a message from an elderly gentleman claiming he is actually him in the future. The young man is amused and drunk, so he decides to friend him. However, when he tries, a Facebook message pops up saying "You cannot be friends with yourself." Question: How did Facebook know?!!

There is the paradox of the man who is his son and his dog. A man "Jack" encounters an evil wizard who turns him into a dog "Rover". Rover then has sex with some bitch and out pops Rover Jr. A good wizard then turns Rover Jr. into a human "Jack Jr." who claims Rover as his pet. When Rover dies years later, Jack Jr. gets sad and builds a time machine and goes back in time. Jack Jr. then encounters an evil wizard. Question: Who cleans who's shit?