50th birthday cake ideas?

So this year my father is turning 50. I am in charge of the cake, which is always what I am in charge of for any event as cake is pretty much my life. Though I have sat here for hours trying to figure out a birthday cake idea. I was thinking the over the hill cake, but that has been done so much I'm just not feeling it. So here is where Yahoo Answers comes in, So what should I do? it can't be anything "immature" like boobs or anything like that as this is a family celebration and we have some youngsters that will be there. So yeah, let the ideas start coming!