Do you know your 'athlons'? A guide

Words ending in the syllables 'athlon' tend to send chills up my spine -- being someone who likes to take fitness at my own pace, I'm always wary of races, particularly looooooong ones. But not all 'athlons' are the same. Do you know your 'athlons'? Fitsugar has a quick guide to them:

• Duathlon: Involves two sports -- Running, biking, and then another bout of running
• Biathlon: Also involved two sports, but usually they're cross-country skiing or running and rifle shooting
• Triathlon: A race with swimming, biking and running -- distances vary. The Iron Man is a popular triathlon.
  
• Quadathlon: Involves swimming, kayaking, running and cycling.
• Pentathlon: A race consisting of five events -- usually running, swimming, pistol shooting, fencing and horseback riding. What an ... um .... interesting blend of sports.
  
• And they forgot Decathlon (typically for males): Consists of 10, count 'em, 10 track and field events over two days. Events including running, javelin, shot-putting and so on.
  
• Heptathlon (typically for females): This one consists of seven track and field events.

Are you into any of the 'athlons'? Which one and why?