Is Runner’s High For Real?

A curious reader asks: Is the euphoria that runners and other endurance athletes claim to experience when they exercise real? And if it is, what’s the shortest route to get there?
The increasingly authoritative Wikipedia describes runner’s high as a “widely publicized effect of endorphin production…. which is said to occur when strenuous exercise takes a person over a
threshold that activates endorphin production. Endorphins are released
during long, continuous workouts, when the level of intensity is
between moderate and high, and breathing is difficult.”  But wait: In the next paragraph, Wikipedia warns that “some scientists question the mechanisms at work, their
research possibly demonstrating the high comes from completing a
challenge rather than as a result of exertion.”
Who are those skeptics? Who cares, says Gina Kolata, New York Times health writer and veteran runner: they have now been proven wrong. Kolata cites research recently conducted at the University of Bonn in which scientists used PET scans to track endorphin production and flow in the brains of runners, before and after a two-hour (yes, two-hour) run. The data showed that, indeed, endorphins were produced during running
and were attaching themselves to areas of the brain associated with
emotions. The runners were getting high.
But what about part two of the question? What’s the best way to experience runner’s high? Wikipedia helpfully
suggests that “Workouts that are most likely to produce endorphins include, boxing, running, swimming, cross-country skiing, long distance rowing, cycling, hockey, tennis, weight lifting, aerobics, or playing a sport such as soccer, basketball, rugby, lacrosse, Paintball or American football.”
What about you? What exercise gives you the best rush of euphoria?