Programming Contest

Project Euler
http://projecteuler.net/problems
Project Euler is a series of challenging mathematical/computer programming problems that will require more than just mathematical insights to solve. Although mathematics will help you arrive at elegant and efficient methods, the use of a computer and programming skills will be required to solve most problems.

The motivation for starting Project Euler, and its continuation, is to provide a platform for the inquiring mind to delve into unfamiliar areas and learn new concepts in a fun and recreational context.

ACM International Collegiate Programming Contest World Finals
http://www.ibm.com/developerworks/university/students/contests/acm/index.html
The ACM International Collegiate Programming Contest (ICPC) is a multitier, team-based, programming competition sponsored by IBM. It operates under the auspices of ACM and has its headquarters at Baylor University in Waco, Texas.

Google Code Jam
http://code.google.com/codejam/

Top Coder

http://topcoder.com

http://train.usaco.org/usacogate

 

UVa Online Judge

 

Game Development Contest

https://www.nonamesite.com/web/cs-stem/activities