You don’t have to be real to be popular. So far, fans have downloaded more than 100,000 tracks by the music group 2Gether — and they’re not even an authentic band. 2Gether was born out of a recent fictional MTV movie about the manufacturing of a boy band (think the Monkees meet the Backstreet Boys), and despite the spoof nature of the TV flick, fans have flocked to the MTV Web site to download copies of the group’s songs: “U+Me=Us (Calculus),” “You’re My Baby Girl,” and “Say It, Don’t Spray It.” The site also features a streaming video for “U+Me=Us (Calculus).” As the band, 2Gether consists of Jerry (the hunk), Q.T. (the young one), Chad (the shy one), Doug (the older brother) and Mickey (the bad boy).