If that's too easy, you could try joining Tautology Club, which meets on the date of the Tautology Club meeting.
![[[Person speaks to a second person]] Person 1: You should come to our linguistics club's sesquiannual meeting. - Membership is open to anyone who can figure out how often we meet.](https://imgs.xkcd.com/comics/linguistics_club.png "If that's too easy, you could try joining Tautology Club, which meets on the date of the Tautology Club meeting.")