There is a lot to be said about the after party being better than the actual party, or there would be, if R Kelly didn't always end up rudely cutting in to sing the hook. For a manly man's race with an even better post-run bash, try Warrior Dash.
Started by a dude who used to paint houses for a living in Chicago before the incredibly motivating Jeff Probst inspired him to do more, WD is an American Gladiators-esque 5K race (held Oct. 30) that'll pit up to 6,000 viking-helmet-wearing thrill seekers against one another in a 12-obstacle course situated alongside the Pacheco Pass Hwy, with a post-race celebration of Nordic proportions waiting at the finish line, next to a surprisingly fresh Rosie Ruiz. After conquering all dozen feats of strength, including the fire-jump-required Warrior Roast, the prepare-to-get-muddy Satan's Slip n' Slide, and a speed step through hundreds of tires, race-finishers will enjoy a pint of thirst-quenching Pyramid on the house, with the top three times also scoring a custom-engraved, steel-framed, wood-horned warrior helmet (sure, a wood horned warrior missile might be more natural, but it would freak out Jewish girls). Post-acquiring all your finishing booty is when the real party starts, with ample supplies of beer steins and turkey legs, as well as contests of strength including boulder heaving, knife and axe throwing, and a "Best Beard" competition, aka the MLB Playoffs.
Oh, and don't worry if you can't find your vintage eighth-century Scandinavian headgear, every runner gets a free viking helmet, tee, and participatory neck-hanging bling, unless you're projected to win, in which case Rosie most likely already has you Trapped in the Closet.