(no subject)
I feel horrible asking for this because I was JUST reading it the other day, and I think I got it from this community, but I just can't find it! So I'm really sorry if this was just asked for a couple of days ago!
The title is "Ten Terrible Tuesdays" or something like that, and Sirius brews a memory potion wrong, so when he drinks it, he forgets each day after falling asleep and thinks it's Tuesday every time he wakes up. It was based off the movie 50 First Dates, I think. Anyway, Sirius and Remus get together during the this period, so every time Sirius wakes up, he forgets that they were together.