Travel through time. Travel through space. Figure out what went wrong, and how you can fix it. Save the past. Save the future. Maybe even the present. Meet interesting people. Take them to the movies or something. Try not to lose them at the mall or water park. Don't let bogus gym teachers from the future ruin everything. Hang out with Death and play Battleship. And maybe, just maybe, realize at the end that learning how to play your instruments and say "I love you" was worth all of it.