In December, buzzy Brit band Alt-J's debut album An Awesome Wave won the prestigious Mercury Prize (U.K. album of the year). This month they launched their first major U.S. tour, including a slew of acclaimed shows at the South-by-Southwest music festival. Keyboardist Gus Unger-Hamilton and guitarist Gwil Sainsbury share a few song suggestions for a totally normal dinner party...in the woods...with witches.