Google's Security Challenge.

http://www.eweek.com/c/a/Security/Google-Challenges-Hackers-to-Native-Client-Security-Contest/
http://code.google.com/contests/nativeclient-security/faq.html
http://code.google.com/p/nativeclient/

Google Challenges Hackers to Native Client Security Contest
Google wants hackers to take their best shot at cracking Native Client security. Google is offering prizes for the top five vulnerabilities hackers can find. The contest ends May 5. Google is hosting a contest to get its hands on security flaws affecting its Native Client technology.
Native Client is an open-source research technology for running x86 native code in Web applications. As an incentive, Google is offering five cash prizes, the largest of which is $8,192. Second place is $4,096, third is $2,048 and both the fourth and fifth place prizes are $1,024. All amounts are in U.S. dollars.
The contest will end just before midnight Pacific Time on May 5.