Gig Alert: The Bad Plus at The Jazz Standard, 5/9-5/14Tickets: $35, with sets each night at 7:30 and 9:30 Since 2000, the piano trio known as the Bad Plus has upended any expectations you might have of what a piano trio should sound like. Yes, they use the classic lineup of piano, bass, and drums, but the band’s albums and live sets have featured a mind-boggling array of groove-based original tunes, fractured covers of rock classics, and even a jazzy take on Stravinsky. The ever-metamorphosing piano trio is playing all this week, thru Sunday, at the Jazz Standard; one of the last chances to see them with founding member Ethan Iverson, who plans to leave the trio in 2018.