Math problems with $ rewards

[Razumikhin]

I will list the ones I know
1) Millennium problems (1M $)
2) The Beal conjecture (100K $)
3) Wolfram 2,3 Turing Machine research prize (25K $)

Anybody know others (preferably simpler ones [img]/images/graemlins/smile.gif[/img] )?

[Siegmund]

There are several prize problems with various sponsors collected at mathpuzzle.com/prizes.html - both small and large prizes.

Al Zimmermann's Programming Contests, at www.recmath.org, aren't strictly MATH contests (they are generally won by coders not theory people) but they give small cash prizes frequently.

The Electronic Frontier Foundation's bonus for finding the largest prime number isn't exactly easy to win but is easy to explain.