I just stumbled upon this gem on youtube – the band Scary Pockets and their ultra-tight and funky covers of popular songs. These guys are really good and the guest vocalists that sit in are amazing.
Check out Yesterday by the Beatles, done in a way you have never heard before:
Another really good one is Sweet Child O’ Mine, flipped and funked up:
They have millions of views, so add a few more. Great stuff!