The number Arthur Weasley typed in the call box to get to the Ministry of Magic is 6-2-4-4-2. If you look at the letters that belong to the numbers (old telephones) he spells "Magic".

J.K. Rowling has said that Voldemort's boggart would take the form of his own corpse, because "he thinks that [death] is a shameful human weakness".

And if he stood in front of the Mirror of Erised, he'd see "himself, all-powerful and eternal".