Problem: Had a co-worker's Speed Triple leak coolant all over the place while on a ride. Turned out it was a hairline crack in the radiator.
MacGyverism: Threw in half a teaspoon of black pepper (restaurant packet) in the radiator.
Outcome: Black pepper worked its way to find the small leak and eventually expanded and filled the leak.
Conclusion: Flushed out the cooling system and replaced the radiator.
Disclaimer: Don't drink the pepper flavored coolant.