Summer's Dirty Dozen

Mel Gibson. Lindsay Lohan. Taylor Momsen. See the 12 stars who were very, very naughty this summer

LEVI JOHNSTON

After reuniting with ex Bristol Palin, she ended the engagement, blaming his obsession with fame. Still, Johnston insists that the two are "friends" – just like the woman on his arm at the Teen Choice Awards (left) less than a week later.