.OSK

.OSK file extension

This is the basic program to work with .OSK extension

osu!

osu! osu! beatmap

osu! is a free online skill game in which you need to match circles, slide balls along a track, and spin a circle as fast as you can. This is not as simple as it may seem. The game is rather challenging even in its easier levels. It is also highly customizable. If you like electro and pop music, skill games and Manga-style graphics, this game is definitely for you... (more)

The program works with the following extensions: osk, osr, osz and osz2