Hey o2bn420!
You can get more info at www.hempfest.org
check out the sponsers and the lineup. Some decent pro-pot bands will be there, and a ton of important speakers. Plus it's FREE....
I've never been to Seattle either, but the Hempfest takes place on this huge strip next to the water..Myrtle Edwards Park....
Anyway, i found out about it because of HEADS Magazine, so i have to give them props. Hope you go!