There are those who measure the prestige of an endurance event by the length of time it takes to complete. And sure, there's something to be said for those strong (and crazy) enough to take on 100-mile ultramarathons, double Ironman-distance triathlons, double century bike races or marathon-length swims.
But for those of us who lack the free time, inclination and insanity to attempt such a feat, there are plenty of more accessible events to test our physical and mental limits - without making training a full-time job. So if you want to take on a new challenge, but also want to have a life outside of your workouts, here are 10 tough events to try.
1. Tough Mudder
Tough Mudder is roughly 12 miles of obstacles, including 12-foot "Berlin Walls," a plunge into a "Chernobyl Jacuzzi" (a dumpster full of ice water) and an "Electroshock Therapy" dash through charged wires.
With no timing chips, Tough Mudder is billed not as a race but a team event to be faced in groups. Most take around three and a half hours before picking up an orange finisher's headband for their efforts. Will Dean (who worked in counter-terrorism for the British government) created Tough Mudder as a Harvard Business School project.
2. Spartan Race
Though not as punishing as the Spartan Death Race, which has no set time limit and has lasted as long as 67 hours, Spartan Race comes in three challenging-enough formats — ranging from three to 12-plus miles — that most mortals can attempt.
Race creator Joe DeSena, a former Wall Streeter who once did 12 Ironman triathlons in one year, stresses that Spartan is no mud run or team-building event. It's a race — and a brutal one at that. Athletes must haul five-gallon buckets of gravel, climb walls, flip tires, pull hunks of concrete and run a race-ending gauntlet of Spartan warriors swinging double-sided mallets. Thirty Burpees for each obstacle not finished.
3. Goruck Challenge
If your idea of a good time is wearing a backpack full of bricks while taking orders all night from a former Special Ops guy, then Goruck is for you. Created in 2010 by Green Beret veteran Jason McCarthy as a way to market his $295 military-style rucksacks and provide a taste of Special Forces training, Goruck now draws "classes" of 30 who must work together to haul telephone poles, railroad ties and sometimes each other.
Throughout the event you wear a backpack filled with a water bladder and either four or six bricks depending on your body weight. There's no set time or distance for the Challenges, which begin at 10 p.m. or 1 a.m. and are held all over North America and beyond, but 12 hours and 20-plus miles is typical.
4. Boston Marathon
There are many other U.S. marathons, but none more prestigious (and few more difficult because of hills) than Boston, one of the country's signature sporting events, attracting more than 500,000 spectators. Held annually since 1897, the event is the longest-running marathon in the United States and one of the oldest running races in the world.
The race is held on Patriots Day, the third Monday in April, a Massachusetts holiday commemorating the start of the Revolutionary War. Unlike most marathons, Boston requires runners to meet qualifying times and limits participants to 25,000.
5. Ironman 70.3
In 2006, the World Triathlon Corporation rebranded its half Ironman triathlon events as 70.3 races in reference to the total swim-bike-run mileage (1.2-mile swim, 56-mile bike, 13.1-mile run). The reason? The term "Half Iron" didn't quite do justice to a race that takes most between five and seven grueling hours to complete.
The name change worked. Entries soared overnight as athletes realized they could feel a sense of accomplishment — it is 70.3 freakin' miles, after all — without undertaking the life-consuming training and expense of a full 140.6-mile Ironman. These days, WTC stages 53 Ironman 70.3 events all over the world, including a September world championship event in Nevada.
6. Sea Paddle NYC
There are many ways to see New York City, but perhaps none as unique as by stand-up paddleboard. This 26.5-mile charity paddle around Manhattan, which began in 2007 and is held in August, takes most athletes around five hours to complete.
Along the way, even veteran paddlers are challenged by the wake churned up by boat traffic in the Hudson and East Rivers before finishing under the Brooklyn Bridge. (Though it's a calm ride compared to the choppy 32-mile Molokai-to-Oahu challenge in Hawaii, which requires each racer to have a boat escort.) In New York, participants must raise $1,000 that goes to autism-related charities.
7. La Jolla Rough Water Swim
When a swimming event is held in an area that's also popular among surfers, you know it presents a challenge. Dating back to 1916, the La Jolla Rough Water Swim offers both a one-mile and a three-mile "Gatorman" version.
The 500 Gatorman participants, who start in one wave, follow a technical course with several buoy turns. The race recommends that you bring a buddy to accompany you on a paddleboard. And you better move fast: the course closes after 1 hour and 45 minutes.
8. Ragnar Relay
Round up 11 of your closest friends (or a bunch of fleet-footed acquaintances), pile into two vans, and spend the next 18 to 36 hours running, sweating, and stinking across 200 miles of pavement. That's the Ragnar Relay, created in 2004 and named for a 9th century, adventure-seeking Norse Viking.
These days, Ragnar events are held all over the U.S., attracting those who don't mind sleep deprivation and automobiles with an air of body odor. Runners split the race into shifts that are between 3 and 8 miles in length. Teams launch between 6 a.m. and 3 p.m. on a Friday and the majority finish between 25 and 32 hours later.
9. Mount Washington Road Race
It's only 7.6 miles, but mile for mile the "Run to the Clouds" might be the toughest and most scenic running event anywhere. Runners climb 4,727 feet on an average grade of 12 percent to reach the summit of the highest peak in the Northeast, located in New Hampshire.
The race has its origins in 1904 when George Foster, a medical student, completed the route in 1 hour, 42 minutes to impress his friends. In 1936, some of Dr. Foster's friends organized a race in his honor and now the mid-June event, held annually since 1966, attracts 1,000 runners, though at least that many are turned away by the race's lottery entry process.
10. The Goofy Challenge
Running a half marathon or even a marathon through the flat Central Florida terrain of Disney's theme parks might not be enough of a test for some. For those people, there's the Goofy Challenge, which allows you to run the Disney Half-Marathon on Saturday followed by the full marathon on Sunday in the same weekend.
The races take place in mid-January, and if you finish both races within the allotted requirements, you take home the coveted (and giant) Goofy medal. Want to bump up the degree of difficulty even more? Start the weekend with a Disney 5K run on Friday.