Correction on my previous post of September 6, 2009.

You CAN become insanely bored on a treadmill. Anything over the 2 hour marker should suffice to drive you suitably insane.  Better yet, have your IPod either die on you or refuse to play anything but your 70's Disco Mix; that should be enough for you to strangle the coughing, hacking, perfume doused bastard next you.