Radiohead kicked off the European leg of their In Rainbows tour this weekend with a two-night stop in Dublin, bringing with them a new song "Super Collider." The song had previously been sound-checked by the band, and Thom Yorke used the encore portion of both Dublin shows to try the song out on a live audience with a solo performance. Check out the video above. Also performed during sound-checks, and posted in a video on Radiohead social network waste.central, is Thom Yorke and Jonny Greenwood attempting Portishead's "The Rip," from that group's new album Third. The video, which was posted by Colin Greenwood, shows the duo covering the song backstage at the band's show last month in St. Louis, Missouri.