Cupid's Undie Run, a fun run to raise money for research into curing Neurofibromatosis, is "brief" in more ways than one. The run will take off from Tom Grainey's on Sixth Street at 2 p.m, and although it's just a mile long, it comes with a catch—you're encouraged to go the distance in your most show-stopping Valentine's Day underwear. If heading out the door in your unmentionables is off the table, no worries; crazy costumes are good too. The run is sandwiched between hours of boozy partying for charity, and has been known to bring out folks in everything from heart-covered bras to unicorn head dresses. Though the afternoon is guaranteed to be light-hearted, Neurofibromatosis, a genetic disorder that causes tumors in the nervous system, is serious business, so don't forget to snag sponsors for your sprint to help Cupid's Charity reach its $64,000 goal.