You know that friend that celebrates their entire “birthday week”? Well, say hello to Artpace, which recently wrapped up a yearlong 20th anniversary celebration that included last year’s excellent “Hare and Hound Press + Artpace: The Art of Collaboration” exhibition, the Texas premiere of Christian Marclay’s video projection Guitar Drag and the publication of Felix Gonzalez–Torres: Billboards, a book documenting a 2010 exhibition…