For a true taste of the local Seattle culture in the holiday season, try to secure a seat at the Fremont Arts Council's Feast of the Winter Solstice. It shows a very intimate and locally-flavored side of Seattle's arts and activist community. It is a potluck dinner for all the volunteers of the FAC that includes amazing art installations, drumming and dancing, and a sun effigy to which you tie notes of what you wish to let go of in the coming year. At the end of the evening, it is burned. This is a wild, druidic affair that is also a great time to meet some of the most community-oriented Seattlites in the city.
You bring your favorite food and whatever you wish to imbibe. They are also now asking that if you are not a FAC member, that you join ($25) and contribute a donation to cover costs ($10). This is voluntary, however. If you are strapped on cash you can always, in the spirit of community, volunteer to help with the set up or clean up... another great way to meet the locals!
If you are coming in the summer, then the MUST SEE is the Summer Solstice Festival Parade, on the weekend closest to June 21st.... costumes galore, belly dancers, men in kilts, and naked bicyclists (and that's just the AUDIENCE!!) But, more on that later.