1) JKR said if Voldemort ever saw a boggart, it would be his own dead body since his greatest fear was death
2) Dumbledore is an old English word for bumblebee
3) Rowling was original going to kill Arthur and Ron Weasley but couldn't do it so she instead killed Remus and Tonks
4) Sirius Black and Fred Weasley, two pranksters from different generations, both died while laughing
5) During PoA Trelawney refuses to sit at the table saying that when 13 sat at the table at the same time, the first to rise is the first to die, well, Scabbers was in Ron's pocket meaning 13 people were already at the table, Dumbledore was the first stand, he died first. This also happens in OoP when the 13 members of the Order of the Phoenix are sitting together and Sirius stands up first
6) While filming the kissing scene between the horcrux versions of Harry and Hermione in Deathly Hallows – Part 2 Ron had to be removed from set for laughing hysterically