Either way, with a 5:00pm local time kickoff, it'll be getting chilly by the end of the game.
I plan on staying at the Boulder Marriott, which is right near campus. As far as I can tell, it has been sold out for some time. I found decent hotel options about 10 miles from campus, some with fairly low ($100-125/night) rates. There are flights from Atlanta to Denver still in the sub-$300 range.
Also, the Colorado Bulldog Club will host a party at The Business Field. There are tickets available (for $26/per until Labor Day, then $32/per h/t BulldogBry) and include complementary beer....yeah, that'll be fun.
Boulder is known for its more laid back vibe. It'll be fun visiting a