I started listening to rock when I was around seven (or, at least, that's the youngest age I can remember). My mom and her...err.... fifth boyfriend were listening to the radio, which played songs from various rock bands, mostly AC/DC. A couple years later I was given an AC/DC CD. Around the same time, my mom listened to a CAKE CD of her's, which is how I got into them.
I got into Muse from Geetar Hero, along with Dragonforce, and every other band I like, I've heard on the radio.