The nonprofit North Cascades Institute (2105 Hwy. 20, Sedro-Woolley, 360/856-5700, ext. 209, www.ncascades.org [1]) offers a wide spectrum of classes, lectures, kayak trips, whale-watching cruises, bird-watching safaris, photography training, and even poetry workshops.
Many of the trips are exceptionally good deals; for example, a three-day hiking trip guided by wildlife biologists or professional photographers costs only $185.
You’ll find something going almost all the time between April and December.
Links:
[1] http://www.ncascades.org