what the fuck that bands in similar artist are similar? Similar artists = bands that most Offspring listeners also listen to. In this case, since Offspring is kind of mainstream, you're left with those 8 bands. GD, B182, and S41 are punkish, RHCP and Nirvana had elements of punk early on, and Metallica and LP are hard rock (kind of like The Offspring in some of their songs).
Ironically, both times I got speeding tickets I was listening to the most fitting Offspring songs, first time it was DUI second time it was Bad Habit. I don't listen to those songs on the road anymore :-D But basically, any Offspring song, any time...KIK ASS. All I Want = my theme song, and Warped Tour 2005 = best day of my fucking life.