If P = NP is proven and generally believed by 12/31/10, then Ron will pay me $50. If P ≠ NP is proven and generally believed by 12/31/10, then I must pay him $10. Under any other circumstances, no money changes hands.
Update (again): we have renewed our bet (again):
If P = NP is proven and generally believed by 12/31/20, then Ron must pay Kevin $50. If P not = NP is proven and generally believed by 12/31/20, then Kevin must pay Ron $10. Under any other circumstances, no money changes hands.
Update (yet AGAIN in 2021): we have renewed our bet (again):
If P = NP is proven and generally believed by 12/31/30, then Ron must pay Kevin $50. If P not = NP is proven and generally believed by 12/31/30, then Kevin must pay Ron $10. Under any other circumstances, no money changes hands.
Admittedly the stakes are not high, but are there any other takers?