[MrTechCenter]

Forgot to mention this before, but a lot of the hotels near the airport have complimentary airport shuttles. Since pretty much everybody staying at those hotels were there for Champs, the shuttle wasn't being used in the morning much (or even really at night for that matter) so we just took the MetroLink to Terminal 1 and called the shuttle to pick us up and take us back to the hotel and vice versa in the morning. Luckily, the airport is the last stop on the line, so the trains are empty when they get there and you don't have to worry about finding room for everybody.

EDIT: The shuttle thing will only work if you have a smallish team there.
Also, you have to be a little careful when coming back at night, especially if you're coming back later after doing stuff downtown after the dome closes. There are some VERY shady characters on the Metro if you're riding late. When we were coming back from RoboProm, one of our kids was offered drugs. Yes, he declined.