I liked a lot of the mashups that Glee did. I haven't really kept up with the show since season 2 though due to a slight loss of interest, but I do sometimes listen to the songs that they come out with.

One of my favorite mashups at the moment is called "Crazy In The Deep". It's a combination of Adele's "Rolling in the Deep" and Gnarls Barkley's "Crazy". Then there's another one by DJ Earworm that combines a song from the musical Damn Yankees called "Whatever Lola Wants" with a Nelly Furtado. It's just so catchy.