Despite the strange name which makes it sound like some kind of anti-laxative, Ring Pass Not is another of these strangely addictive games. Once it's loaded you can, if you wish, click on "Options" and untick the "Music" checkbox to stop the annoying pseudo-medieval background tune.
The game is a puzzle which involves creating a ring by matching paired segments by their colour or shape. As you progress, constraints are applied which make this more difficult, although these can be offset by bonus tools which you accumulate for special arrangements or combinations of colours or shapes.