Lance Armstrong is probably having sex with Paris Hilton:

COULD it be that Lance Armstrong has taken a break from incessantly working out with his new best friend, Matthew McConaughey - to spend time with Paris Hilton? The two showed up to the Key Club in L.A. Tuesday night to catch the band the Vacation. "They came together, they hung out and left together," said our spy. They missed Linkin Park's Chester Bennington hopping onstage with main attraction Metal Skool and belting out a few songs.

I wonder what was more difficult for Lance? Conquering the steep climbs of the Col du Tourmalet and the Alpe d'Huez on his way to 7 straight Tour de France victories, suffering through multiple grueling sessions of chemotherapy while being given less than a 10% to live, or navigating through the treacherous "innards" of Paris Hilton and NOT catching an STD. I vote for the latter with the chemo sessions coming in a distant second.