A ticket presale for fans begins today (8/15), while the general public on-sale starts Saturday (8/18). One dollar from each ticket sold through the presale will go to a relief fund for victims of the I-35 bridge collapse in Minneapolis, according to a press release. Details are available at Atmosphere's ticketing website.

The group, which consists of vocalist Slug (real name Sean Daley) and production wiz Ant (Anthony Davis), is currently working on its sixth studio album, "When Life Gives You Lemons ...," which is due next spring. The record will follow 2005's "You Can't Imagine How Much Fun We're Having," which snagged the No. 1 spot on Billboard's Top Independent Albums chart and reached No. 66 on The Billboard 200.

While fans wait for the new album, Atmosphere is tiding them over with the "Sad Clown Bad Summer Number 9" EP, which was released last month. The song "Sunshine" from the set is streaming at the duo's MySpace page. The group also plans to release the limited tour series EP "Sad Clown Bad Fall Number 10."

Atmosphere, which introduced its style of Midwestern hip-hop in 1997, is one of a few alternative, indie rap acts that regularly sells more than 100,000 copies of any given album, according to entertainment publication The A.V. Club. Despite being courted by major labels over the years, the group has stuck to its indie guns, signing a licensing deal with punk label Epitaph.