Jimi Hendrix was born in Seattle and it is where his music career started. To commemorate him and his music, Paul Allen (co-founder of Microsoft), founded the Experience Music Project Museum. After a few years the focus of the museum has changed, and it started displaying memorabilia and artifacts commemorating other Seattle-based artists as well (e.g. Nirvana). A part of the museum is also dedicated to science fiction and technology, especially those technical elements behind some of the recent famous movies/TV series (like Avatar and Battlestar Galactica).
We enjoyed the exhibits dedicated to Nirvana and Avatar, but we were not at all interested in the exhibit dedicated to Battlestar Galactica. I guess you have to be a fan of the movie to enjoy it. We also had a lot of fun exploring the Guitar Gallery which documents the history of electric guitar development, and an interactive Sound Lab, where one can have fun learning the basics of playing various instruments and mixing music.
The building in which museum is located is also quite a sight, thanks to its architect Frank Gehry:
The Avatar Gallery:
The Sky Church:
The Nirvana Gallery:
The Guitar Gallery:
Neal Potter's "Roots and Branches" statue:
The Sound Lab: