Bloomsday is a commemoration observed annually on 16 June in Dublin, Ireland and elsewhere to celebrate the life of Irish writer James Joyce and relive the events in his novel Ulysses, all of which took place on the same day in Dublin in 1904. The name derives from Leopold Bloom, the protagonist of Ulysses, and 16 June was the date of Joyce’s first outing with his wife-to-be, Nora Barnacle, when they walked to the Dublin village of Ringsend.
At least, that’s the official version.
There are those who say that in truth, the date Joyce chose to set Ulysses on was not to commemorate his first date with Nora, but rather, the first time the two had any sort of sex (in this case, consisting of her masturbating him to orgasm).
But feel free to continue to believe that the author of Ulysses was a chaste man if it makes you happy – I merely suggest that if you wish to maintain this belief, you never read the book itself.