Calvin and Hobbes by Bill Watterson for September 01, 1987
Hobbes: Are we going to travel into the past or into the future? Calvin: Well, I suppose if we went into the past, I could ace any upcoming history exams in school. That might be useful. Calvin: But if we went into the future, we could swipe something and pretend to invent it when we got back. We could be rich. Hobbes: The future it is, then! Calvin: Right. Once I'm rich, I can hire somebody to take all my dumb tests!