"I Gotta Feeling" (Cover by the Cleverlys; originally by the Black-Eyed Peas in 2009)
Unlike the "Pickin' On" series, the Cleverlys do bluegrass covers of popular music with an intentionally (for lack of a better word) "wacky" approach. The skill is certainly there, and plenty of creativity - but they're also... ridiculous.
When it works, it's a great bit. (When it doesn't, it can be rather annoying.)
I think this particular cover lends itself well to the silly approach. I'm not always a fan of "novelty" music, but I keep listening to this one, so...