Look into doing a berliner weisse. I did one a few months back, soured half the mash at +\- 110 degrees for about 36 hours prior. Added the sour mash back into the rest of the mash, heated it to temp and proceeded as normal. Worked out quite well actually, one of the better beers I've made.
EDIT: Just realized I did some major necromancy on this thread, sour mashes are great though!