The "Pepero" (빼빼로) candy is shaped like the number 1, so every January 1, January 11, November 1 and November 11 is "Pepero Day" in Korea, which is apparently the result of some great marketing by the Lotte company since this snack flies off the shelves on these four days each year.
This year, November 11 is even more meaningful because it's 2011, so the date can be written: 11-11-11, making it the mostest, bestest Pepero day in a hundred years!