This weekend is the Fat Tire Festival in Fruita, which means beer, biking and not many free campsites. If you want to hob nob with your mountain bike friends, it's a great weekend to be in Fruita. If you want to ride, next weekend might be a better choice.
Worth seeing, though, is the Clunker Crit -- an in-town race on old cruiser bikes. See video of it here.