Of the seven Millenium Maths Problems, each of which is worth $US1 million to the person who can solve it, the Riemann hypothesis is perhaps the most difficult to crack. Reckon you have what it takes?
In this video, my favourite mathematician, Edward Frenkel, explains the basics of the theorem. If you can puzzle through it, you could make yourself a packet -- but it might just be the hardest $US1 million you ever make. [YouTube]