We've been carrying Mac's Field Guides (the Northwest Backyard Birds and Northwest Coastal Water Birds ones) and putting stickers on the birds we spot. Among the ones stickered so far: the yellow-billed magpie, the California gull, the cedar waxwing, and the Western bluebird.
An American robin couple has been busy at work collecting grasses, twigs and other nesting materials from our yard, but we haven't been able to locate their nest yet.
We also went to the nearby Randall Museum, which has a great bird exhibit and was perfect for us, because we got to see many of the common (and some much less common) birds of the area close up. The cawing raven was everyone's favorite.
Also, we've played Christine Berrie's Bird Bingo, which is really great. (We recently also got the Bug Bingo as a present, and will probably use that too later on).
Among the books we've used are An Egg is Quiet, and DK Eyewitness Books: Bird. Photographer Sharon Beals also has a beautiful book out about birds' nests.