General fact: 28 is the number of Chinese constellations, "Xiu" or "mansions" (a literal translation), equivalent to the 12 western zodiac constellations.
Mathematical fact: 28 is the sum of the totient function for the first nine integers.
Trivia: 28 is the average number of minutes in a day that kids in the U.S. between the ages of 2 - 8 spend coloring.
Historical date: January 28th is the day in 1878 that Yale Daily News becomes the first daily college newspaper in the United States.