This September 21st at the Merriweather Post Pavilion, Virgin Mobile will once again put on its free festival, featuring marquee names in a personality clashing melange. At the top of the bill are Vampire Weekend and Robin Thicke, which means there’s at least a chance for some live “Blurred Lines” cross-brand synchronicity. Others on the lineup include MGMT, CHVRCHES, Washed Out, Icona Pop, Sky Ferreira, the Avett Brothers, and more. Tickets will be available, freely, on August 25th. Here’s more info.