Go Play NW 2008 will be held at the Watertown Hotel in Seattle's University District, May 31-June 1 2008. Attendance this year is limited to 75 participants! Pre-registration is $40 for both days, and will increase after May 15, so sign up now! Visit the Go Play NW Wiki for more information.
Also, see the nifty T-shirt design by John Harper in this thread on the Story Games forum.