Here’s the story of a lovely Smashing Pumpkins show, which featured two surprise guests, including a member of The Brady Bunch. Barry Williams, who played the eldest Brady son Greg Brady in the classic ’70s sitcom, joined Billy Corgan and company onstage during their pre-Lollapalooza concert in Chicago on Wednesday. They rocked a rendition of the very Brady classic “It’s a Sunshine Day” with Williams on lead vocals. Auf der Maur played in the Pumpkins from 1999 to 2000 following the departure of original bassist D’arcy Wretzky. The Smashing Pumpkins will perform a headlining set at Lollapalooza on Friday night, marking the first time they’ve played the festival since it moved permanently to the band’s hometown of Chicago in 2005.