While watching the guys taking part in the triathlon on Sunday I kept looking out for any amputees. I didn't see any and assumed that amputees don't do triathlons. Can you blame us -- haven't we suffered enough already?

However, a quick search of the internet proved me wrong:
Paul Martin's website
More on Paul Martin from the St Petersberg Times
Wired: The Bionic Triathlete
San Diego Triathlon Challenge
Article on Rudy Garcia-Tolson

....that's my excuse out the window, then. It seems that "I've only got one leg" just won't wash. Maybe next year...