What is a sleeper hit exactly? Let's wiki it!
A sleeper hit, a.k.a. surprise hit (often simply called a "sleeper"), refers to a film, book, single, album, TV show, or video game that gains unexpected success or recognition.
So post some of the sleepers, and while the definition says they also acheive success, let's look for cult classics as well that stayed under the radar but are still special to you.
The Lunar Series
Most games from Working Designs are usually very successful and also rare and Lunar is no exception. These remakes of the Sega CD classics are great fun, and also not very well known! I suggest checking them out if you know someone who has them.
Recently remade on the Wii, this is a classic platformer that who knows many knew about.
Keep the list going and if it's successful we can talk about other consoles too. I love this kind of stuff.