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.