...an explanation is probably needed for those who are unfamiliar with Sweet Adelines.
Sweet Adelines is an organization of women who love to get together and sing barbershop music. And barbershop music is a style four part harmony a cappella music. You can click here to see an example. (Sorry to provide a link instead of embedding it, but embedding has been disabled for this video.) Barbershop music is really great, and is a lot of fun to sing.
Choruses from all over the world will be competing, and I'll be rooting for the one from my hometown, Pride of Portland. Fortunately, I can embed a video of them in this post. In the video they aren't singing typical barbershop music, but oh well. It's still Pride of Portland.