You know you want to. Dust off that cowbell and give it the honor it deserves by making it's lovely sound the "core" of the song! It can be full out cowbell solos or just a song with heavy cowbell influences. Take a beater and ring a "real" one, or find some fancy sound effect variety (not nearly as therapeutic). The cowbell has different sound qualities depending on where you hit it, and of course, if you are a true hardcore cowcore person, you can get multiple bells of different tones!
A sample of mine from 2015: https://soundcloud.com/darci-strutt/20150823lonelycowbell
Who's in? Tag them #cowcore so we can find each other!