I think I'm going senile. (Or maybe it's just a side effect of being a math professor.) On Tuesday of last week, I forgot to go to a class. (It meets at a different time on Monday, Wednesday, and Friday. What really happened is that I forgot it was Tuesday, and the class started half an hour earlier than I thought.)
Then on Wednesday of last week, I forgot to leave class. (At least I forgot to get my stuff. I must have let a student distract me out of the classroom, then forgot I left all my stuff spread out across the desk until I happened across it again four hours later.) Yesterday I discovered I left all of my stuff in the classroom again.
I told my colleague across the hall about this, and she asked me when I came back from class today if I had all my books. I laughed, then left my umbrella in the hallway after I got my door open.