That was a great game. Duke 71-70. The Tar Heels played kinda sloppy though.
There is also a legend that dates back further than the Civil War:
When British General Cornwallis' troops tried to cross into North Carolina, they found a thick layer of tar dumped into the river to slow them down. When the redcoats finally struggled through to the other side, they were black with pitch. Any invader of North Carolina, it was said, would get a tar heel. (UNC was founded in 1789, and NC is "the Tar Heel state")
It is true, that the most popular origin of Tar Heels holds that Confederate troops from North Carolina stood in a fierce Civil War battle and saved the day after supporting troops fled. "God bless the Tar Heel boys," was a quote attributed to Robert E. Lee. North Carolina lost more soldiers in the Civil War than any other state, I believe.
This basketball rivalry has been going on since 1920, and in many people's hearts - it's the greatest rivalry in all (US) sport.