Dulles is the closest by far, probably 20 minutes at most from the event. If you're renting a car, you may want to check into either National (Reagan National - I think it's DCA)which is about an hour away, but right next to DC and has a metro stop or BWI-which is about 1.5 hours away. I've found that getting tickets out of BWI can really affect the price. US Air to denver out of Dulles is about 439 dollars more than BWI. So if you've got time to burn, it may be worth it
