I've been getting a bit carried away with my effects pedal lately...
This one uses a guitar loop. The harp part is a bit too repetitive for me, but I find it tough playing only over the I chord.
This one features some ridiculously over the top rock-god style guitar wailing to mask my poor fretwork ... but I had a lot of fun doing it. It's a Jimi Lee backing track.
And finally a quiter one using a strange guitar patch I quite liked.