Cascade Barrel House's weekly "Tap It Tuesday" program at 6pm often enlists a guest tapper to take a mallet to a live barrel of something really amazing. Beware, there is a reason they call it a "sour shower" - some tappers have managed to spray the pub with a shower that shoot more than 20 feet across the room! You can view one such video here: http://www.facebook.com/video/video.php?v=1720555767191
If you are coming to town and want to be a guest tapper, it's wise to email ahead of time and ask if there is an opening: cascade.sours@Gmail.com