Alex turned 9 last month. We just celebrated as a family, but he planned the whole thing. He wanted a Harry Potter cake (he recently finished book 5), and he made up a bunch of Harry Potter games to play. He even mapped out a Quidditch game for the backyard, brooms and all. I think we'd need about 20 people to actually make it work, but we faked it. He also wanted to go to Five Guys for lunch. We happily obliged. Later we took advantage of the nice weather and my new bike and went for a family bike ride. We've done this a couple of times now, and each time I'm impressed at the boys' endurance, and at Wesley's ability to fall asleep in an uncomfortable seat while wearing a big helmet.
As for the spoils, Alex got a microscope, a crystal growing kit, a plush version of an amoeba, and a Harry Potter game for his DS.