To run quickly out of your house (apartment, etc.) in your underwear to get something when it is not worth gettng dressed.
"The paper boy delivered the paper to my front lawn at 5 am, so I made a quick undie run to get it."
by randomhell February 7, 2007
An organized race where speed and competition are replaced by beer and little clothes. This race usually takes place at the end of finals week in a crowded downtown area of a college town.
by Violated Centaur March 13, 2005