It's MTV's second annual Musical March Madness! MTV News took the 64 biggest names in rock, split them up into four regions, assigned them seeds and puts them up against one another in a single-elimination series of match-ups in a winner-take-all contest. We're leaving it to you to decide an actual champ in this field of 64, so over the next few weeks, fan voting will determine who will emerge as this year's champion. It's all about the fans, and the artist with the most passionate fan base will score the awesome Musical March Madness trophy!

With the voting now active on the match-up below, the second round games are now completely open. The winners of these pairings will all advance to the Sweet 16, where the voting windows get shorter and the competition even more intense.

Voting for all second round match-ups will close on Sunday, March 27 at midnight. As always, you can follow all the voting here.

(2) Radiohead vs. (7) Owl City

Owl City are very much the Butler of this tournament, scoring unlikely victories against bigger, faster and more famous squads. They had an improbably hot run in last year's Musical March Madness, and this time around they dispatched of indie darlings the Decemberists in relatively short order in the first round. But they'll have to take on a very game Radiohead team who are coming off a big win against TV on the Radio. Which group will keep marching toward immortality and which will have to pack it in until next year? Your votes will tell the tale!

Watch the breakdown of the first round and a preview of round two!

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Check out the Musical March Madness bracket and be take a look at the hoops-centric photos of some of the tournament's biggest bands.