March 3rd! It's Mii day!

Serious answer: Higurashi no Naku Koro ni. It's a very excellent anime with two seasons, and the visual novel it's based off is equally if not more so great (never played it for myself, but I've heard wonderful things). No clue how the manga adaptation fares. The horror in this anime is very nice, the mystery's very interesting, and- it's just awesome. The series has moments where it could easily be mistaken for a sunny school comedy series, but it easily could transition into something absolutely creepy and/or intense. I like this show indeed.

I actually started off just with the manga and found out it was an anime later on. I found the manga to be a lot more suggestive than the show. I like the manga more.