A canadian fireline worker I had grounding for me last year told me about a real nasty one. I haven't been game to try it yet, I think I'd have to be ready to go straight to punches.
This trick really only works with guys who have big asses, and is best left for summer. You pick up some of the sugar sachets they give you at coffee shops. Throw 'em in your pocket and keep 'em handy. Keep an eye on your target, and wait for him to bend over to pick something up like his saw. Guys with big fat asses are generally big fat bastards, so they don't bend at the knee to often and they move slow. You should see it coming from a mile away. As he starts to bend over, rip to tops off a couple of your sugar sachets. As his shirt lifts up and exposes his butt crack, pour the sugar down in there.
In the heat with all that sweat... it wont take long at all until that sugar turns into sandy syrup. The stickiness and chafe must be enough to drive any man crazy. Apparently it's not unheard of in canada, all I can say is they must be real patient people. If anyone tried something like that in aus I think it would end with a burial.
Shaun