Hi all, please post/share the student coding/programming /robotic competitions
in this thread. So others may also can participate and take the advantage of
those.

Here are few that I know.

General
Google summer of code :- http://code.google.com/soc/
Imagine cup :- http://www.imaginecup.com/
Robo Cup :- http://www.robocup.org/
IEEE :- http://www.ieee.org/membership_services/membership/students/competitions/xtreme/index.html
java cup :- http://javaunlimited.net/contests/java4k.php
Obfusticated C competition :- http://www.ioccc.org/


Mobil
Android :- http://code.google.com/android/adc/
iphone :- http://developer.apple.com/wwdc/ada/

Olympaid
math olympaid :- http://www.imo-official.org/
hacker olympaid also exists , don't know where are the links.
International Olympiad in Informatics :- http://www.hsin.hr/ioi2007/
.. too many other olyampaid are also available.

and I also found some more here :-http://www.tenouk.com/cpluspluscompetitioncontest.html

[add your links too and report the broken links]

Yahoo!! Do hack-days where you have to do something novel using web APIs... they have the OpenHack's and then the HackU's which are universities.