Honolulu Marathon (Honolulu, HI)
Hunter S. Thompson, covering the Honolulu marathon for ESPN, asked a question that most runners have forgotten by the time they're doing marathon distances: "What kind of sick instinct, stroked by countless hours of brutal training, would cause intelligent people to get up at 4 in the morning and stagger through the streets of Honolulu for 26 ball-busting miles in a race that less than a dozen of them have any chance of winning?"
There are lots of good answers or none, depending on whom you ask. But if you plan on busting your balls for 26 miles, you may as well do it in Honolulu. Besides requiring no qualifying time to enter, this marathon features a luau on the Friday before the race and free shiatsu massages at the finish. Plus, the run takes place mostly along the waters of Maunalua Bay and Mamala Bay (including Waikiki Beach). The first ever Ironman triathlon in 1978 included the same course as the Honolulu marathon (now it's on the Big Island).
More Information: Honolulu is pay-to-play, with no qualifying time and no limit on the number of participants. [Second Sunday in December; honolulumarathon.org]