Now, I doubt you'll be surprised to learn that I'm not a music aficionado. (Quiet peanut gallery!) Some things do catch my ear though, and lately that has been the mashups on Glee. Anytime I hear them, I stop what I'm doing and listen. That never happens to me. Here are my two favorites.
This first one, a mashup of Singing in the Rain and Umbrella started it for me. Fascinating!