Mud pits, banana costumes, ice cream flavor identification . . . these are some of the summer’s more idiosyncratic competitive events. Most require advance registration, with prices increasing as race dates approach. —Sam Adams
Chicago Beachathon A four-mile race along the lakefront involving eight “obstacles,” including hula dancing and bingo. There are prizes for the top finishers in several categories—for those wearing a grass skirt, Speedo, or dressed as a banana—as well as the fastest competitors. A party with live music and Landshark beer follows. 
Sat 6/26, 9 AM, North Avenue Beach, 1600 N. Lake Shore Dr., chicagobeachathon.com, see Web site for packet pickup dates, $40-$60.
Great Urban Race Teams of two complete a dozen challenges, including puzzles, scavenger hunts, and physical activities. Last year’s challenges included tae kwon do, crosswords, and charades. Sat 7/24, registration at 11 AM, race at noon, starts at Joe’s Bar, 940 W. Weed, $50-$70 per person, 773-770-6032, greaturbanrace.com.
Mudathlon A three-to-four-mile race over a muddy course with 20 obstacles. Participants crawl through mud pits, climb over wooden spools and mud-soaked cargo nets, and have paintballs shot at them, among other challenges. A party follows with food and beer for contestants. Sat 7/24, 9 AM, Graeber Family Farms, 236 S. 200 W., Valparaiso, Indiana, 937-751-2840, mudathlon.com, $75.
Muddy Buddy For this relay race, teams of two switch off between running and mountain biking, completing obstacles at the end of each leg and finishing up by crawling together through a mud pit. Packet pickup Sat 7/31, 1-5 PM, Columbia Sportswear, 830 N. Michigan, race starts Sun 8/1, 7 AM, Mini Muddy Buddy (4-13 years) at 9:45 AM, Indian Hills Farm, 16N503 Powers, Gilberts, muddy-buddy.competitor.com, $150 per team, $15 per person for Mini Muddy Buddy.
City Chase In this citywide scavenger hunt, two-person teams race to find and complete challenges like milking a cow or rappelling down the side of a building (activities from previous competitions; they change each year). Travel only by public transit or on foot (no bikes, skates, etc). A clue sheet will be handed out at the starting point, which is TBA. Sat 8/21, registration at 8 AM, race at 10 AM, 312-850-8196, citychaseusa.com, $190 per team, 18+.
City Solve Urban Race A race where “brains beat brawn”: teams of two to six people travel the city by foot and public transit, solving pop culture puzzles and math problems and taking on challenges like bowling a strike or identifying an ice cream flavor. The winning team gets $300 and a shot at the $5,000 prize in the national competition; teams of more than two aren’t eligible for prizes. Sat 9/11, registration at 11 AM, race at noon, starting point TBA, $40-$60 per person, citysolveurbanrace.com.
Urban Assault Ride Cyclists ride in teams of two to a dozen-odd checkpoints, stopping for activities like three-legged races and riding mini bikes (obstacles change each year). The event ends with a party that includes contests and free New Belgium brews for participants. Packet pickup Sat 9/11, 11 AM-2 PM, race Sun 9/12, 9 AM, starts at Murphy’s Bleachers, 3655 N. Sheffield, 303-408-0747, urbanassaultride.com, $30-$65 per person.