One of the perennial questions Christians ask when we're bored is, "Does God have a sense of humor?" The answer is usually yes, but the reason varies. "Of course. Have you ever looked at a giraffe?" or "He must, since he made my goofy kid brother. Hur hur hur." or "He must because we do."
Now, I don't think that God has a sense of humor because of giraffes (though giraffes are pretty funny), and I don't think anybody really believes God has a sense of humor because of their goofy friends or relatives. I think the fact that humans have a sense of humor is a good answer, but today I though of a better one: What makes me so certain that God has a sense of humor is the fact that nothing in this world delights me more than being made to laugh by my child.