I would like to make a small proposition.
I have two possible founding dates for the Chicago Chess and Checker Club, later called the Chicago Chess Club, of which Richard Verber was the president in the early 1970s. I’ve seen several references claiming that the club was founded in 1870. However, as far as I can tell from newspaper accounts, the club was founded in 1891, two years after the dissolution of the original Chicago Chess Club on Dearborn Street (1857–1889, per the Chicago Daily Tribune).
Whoever is first to provide me with authoritative evidence proving one founding date or the other wins an autographed baseball.