I've been using mustard packets from fast food places on hot rides as "cramp-breakers" and they seem to work, at least at a placebo level... haven't tried it in a race yet which of course is the real test.

Yesterday, 71 miles, three flats, didn't finish til almost 11:30 but every time I felt cramp's coming on, popped a packet (with a bunch of water, duh). No cramps.