Fait mathématique: 7880 is the maximum value of n so that there exist 4 denominations of stamps so that every postage from 1 to n can be paid for with at most 26 stamps.
Culture générale: 7880 is a boring number.
Date historique: July 28th is the day in 2005 that the Provisional Irish Republican Army calls an end to its thirty year long armed campaign in Northern Ireland.