I'm now playing with a group of guys and we are doing a lot of this kind of stuff (at least at rehearsals). Takes me back 30 years when what we played actually made our juices flow. I'm getting better at this rock organ thing (I've always liked it, just never played it).
http://www.youtube.com/watch?v=1qBHUsGVOp4&NR=1

luv that rock/funk organ (@ 2:19).

chas