Might Mike's Imagine/Jump mashup has a lot of precision in its execution, a great tempo/pitch match. I can't say as it's the catchiest tune I've yet heard, but I can really appreciate the execution.
John Lennon/Van Halen mashup: "Imagine a Jump"
Read more in Music at Boing Boing
I write books. My latest is a YA science fiction novel called Homeland (it's the sequel to Little Brother). More books: Rapture of the Nerds (a novel, with Charlie Stross); With a Little Help (short stories); and The Great Big Beautiful Tomorrow (novella and nonfic). I speak all over the place and I tweet and tumble, too.