Why Didn't Darwin Write a Bedtime Story?

Bug has a dinosaur book and toward the end it talks about how when you see people fighting dinosaurs in movies, that could have never really happened because people weren't on Earth yet when the dinos roamed.  He must have really been digesting that because yesterday (about three days after we last read that book), we were laying down for his nap and he says out of the blue "where did people come from?  Dinosaurs come from eggs, but did people come from eggs, too?"  I thought this was going in the direction of "how was I born" and I went on to explain how mammal babies are born alive and so on, but he took it one step deeper... "after the dinosaurs died, when did the people come?"

How do I explain evolution to a three year old???  I couldn't possibly expect him to understand early homonids and how we came from the apes over millions of years of evolution!   Though, I tried.  It didn't go well.  I actually think we left off with him not believing anything I said anyway.  The conversation ended with him telling me that people came from dinosaur eggs after the last dinosaur died and then he was off to some other (easier) topic.

We'll have to pick up this conversation again.  In about eight years.

September 9th - UPDATE:  

He was right!  People did come from dinosaur eggs!!
I just remembered this photo-op from the animal park we visited on vacation.  Ha ha! Too funny!