Well, usually I'm pretty terrible at riddles anyway ... but that one is quite well-known. How about this one (it is quite popular too) - I am on 4 in the morning, 2 in the afternoon and 3 in the evening. What am I?
Lol it's called the riddle of the Sphinx. And the answer is a human. Because in the morning of their life they're a baby on 4 legs (crawling), the afternoon of their life they're middle-aged and standing on 2 legs and in the evening of their life they are elderly and the third leg is the walking stick. Get it?