RAW (Ride Around Washington) every August. Don't have the URL, but you can Google Cascade Bicycle Club (of Seattle) for ride info. They do it every year, it is a week of touring through a different area of Washington state every year. REALLY well organized and supported, and limited to 200 riders.
And, the Olympic Cycling Classic (May 19 this year) in Port Angeles WA. I am doing the organized version this year for the first time, but I have done the whole route in my own bits and pieces...amazing scenery, from salt water beaches to glacial lakes to rivers to mountains... This is a one-day century with metric and shorter options, stuff for kids, etc.
"The best rides are the ones where you bite off much more than you can chew, and live through it." ~ Doug Bradbury