General fact: 388 is a number for which we're missing a fact (submit one to numbersapi at google mail!).
Mathematical fact: 388 is the maximum value of n so that there exist 6 denominations of stamps so that every postage from 1 to n can be paid for with at most 6 stamps.
Trivia: 388 is an uninteresting number.
Historical date: January 22nd is the day in 1957 that Israel withdraws from the Sinai Peninsula.