The Nation's Triathlon
Credit: Getty Images

The Potomac River swim is billed as the most well-marked in the country, with buoys every 100 meters for those a little less confident in their open-water sighting abilities. After the dunk, the tourist-friendly bike and run courses take you through the National Mall and Memorial Parks so you can do a little sightseeing while on the move. It's a great time to be in D.C. as well. You can catch a Nationals game that weekend (they're in town) or sidestep the monument crowds and tour one of the city's relatively new craft breweries, including Bluejacket Brewery, Atlas Brew Works, and 3 Stars Brewing Company.

The Course: Olympic distance (1.5k swim, 40k bike, 10k run)
When: September 7, 2014
Where: Washington, D.C. 

[$175-$195; nationstri.com]