Owen's Age of Empires Workshop
I closed my Age of Empires Workshop because it had very little content on it (to be precise, it had one campaign, and little else). You can still download the campaign below, should you want to:
This is the second campaign I ever created for Age of Empires, and it has migrated to Rise of Rome. I know there are a few 'odd' scenarios in here - you "jump" from a small tribe to a huge battle, and back to a small tribe, but it all adds to the fun. And I know the first couple of scenarios might be too easy, but when I originally designed this, it was made for beginners. It's now quite good for anyone.
For more information on Age of Empires, I'd recommend you visit Planet Age of Empires.