Wikipedia: Cow Tipping 
Examines the evidence that cow tipping is an urban myth.
http://en.wikipedia.org/wiki/Cow_tippingThe Time-Honored Urban Activity of Cow Tipping
Looks at whether cow tipping is truth or fiction.
http://www.truthorfiction.com/rumors/c/cowtipping.htm
The Statics of Cow Tipping
Looks at the physics of trying to tip a cow.
http://em-ntserver.unl.edu/Mechanics-Pages/Matt-Semke/The%20Statics%20of%20Cow%20Tipping.htm
Burning Cow Tipping
A cow tipping game created to promote the movie "Mars Attacks"
http://marsattacks.warnerbros.com/cmp/2-game.html
Cow Tip
Tips on how to maximize fun during cow tipping sessions.
http://littlerock.about.com/cs/littlerockhumor/ht/cowtip.htm
How to go Cow Tipping
Includes a list of supplies, plus a list of what not to do.
http://calstaging.bemidjistate.edu/en3930/lindahl/howto.html
The Straight Dope: Is There Really Such a Thing as Cow Tipping?
Several viewpoints critique the idea of cow tipping.
http://www.straightdope.com/classics/a3_363.html
Cow Tipping at UC-Davis
Description of cow tipping and student discussion on the subject.
http://daviswiki.org/Cow_Tipping
Cow Tipping Machine
Shows how cows are mechanically tipped for hoof maintenance.
http://www.vnews.com/cowtipping/
Cow Tipping on h2g2
Describes rise in popularity of cow tipping and the sports legality.
http://www.bbc.co.uk/dna/h2g2/A476840
