IV) 2) Al Zimmermann's Programming Contests
...
http://www.recmath.org/Contest   (dmoz  2)

IV) 3) Annual Berkeley Programming Contest
...
http://www.cs.berkeley.edu/~hilfingr/programming-contest/   (dmoz  3)

IV) 4) Eurovision Song Contest
...
http://www.eurovision.tv/   (dmoz  4)

IV) 5) Bart's Contest
...
http://bartscontest.com   (dmoz  5)

IV) 6) The International Obfuscated C Code Contest
...
http://www.ioccc.org/   (dmoz  6)

IV) 7) Internet Problem Solving Contest
...
http://ipsc.ksp.sk/   (dmoz  7)

IV) 8) Field and Forest Photo Contest
...
http://www.fieldandforest.com/contest/contestrules.html   (dmoz  8)

IV) 9) iPhotoContest
...
http://www.iphotocontest.com/   (dmoz  9)

IV) 10) Daily Awards Photography Contests
...
http://www.dailyawards.com/   (dmoz  10)