"Pop" is a game I first wrote in Excel 97 ages ago and that I seem to keep re-writing. This iteration is written in jQuery / HTML / CSS and is moderately complete and wholly encapsulated within a single file - just download the HTML and it can play, although it does need net access to get to jQuery.

Pop is effectively a board game where players take turns to increase the value of a cell they own, when cells reach a certain value they "pop" and capture those around them, potentially causing a chain reaction. The winner is the last player standing.