Red Bull Riot Fest headlining group Weezer has announced a fan vote to determine which of their two albums, The Blue Album, or Pinkerton, the group will perform during their festival encore performance on October 9.  Voting began on Wednesday, and fans will have until September 26 to cast their votes.

The Blue Album? Or Pinkerton?

Voting has been sponsored by Chicago’s WXRT, and fans can cast their votes here. The winning album will be announced at 12 noon on WXRT (93.1), as well as online.

There are still tickets left for the Red Bill riot fest, and Weezer fans are encouraged to grab their own quickly—if only to make up for the speed with which the group’s last Chicago performance sold out.

The two albums are considered to be the group’s most successful efforts to date.

The Blue Album, also known as Weezer, features tracks like “Undone – The Sweater Song,” “Buddy Holly,” and ‘Say it Ain’t So,” and is considered the catalyst for Weezer’s mainsteam success.

Pinkerton was released in 1996, and although it was considered a commercial flop at the time, it has since been given a second look—and its due praise—from critics.

Fans will have until  10 a.m. CST on September 26 to cast their votes and have a say in Red Bull Riot Fest’s headlining show.

For full Red Bull Riot Fest schedule, click here.