The Peace Tower, created by Mark di Suvero and Rirkrit Tiravanija for the Whitney Biennial, now has an online version: Jon Hendricks, artist and archivist for Yoko Ono (along with former Walker Education staffer Meredith Walters and others), has created a virtual tower, made of works submitted via the internet by artists (click here to add your own). Before you go, make sure to sign the peace petition.