A good way I have used is, each member of the band brings a book to rehearsal, player 1 chooses a page number, player 2 paragraph, P3 line & P4 number of word along line. It can be done a few times till you come up with something you like.
I was in a band called "Dr White & the heavy Bleeders" in the late 70's, don't think you would get away with it now. Still makes me smile though.
Taz very glad BIGd