Astrology, from GanX Games is an interesting tool which allows you to guess at the compatibility of two people, based solely on the month they in which they were born.
Making use of numerology and other esoteric traditions, Astrology is capable of calculating the compatibility between your two chosen subjects. It works fairly simply and avoids giving you too much information which might be confusing.
A victory of simplicity, Astrology's interface asks you to just pick the star signs of the two people you wish to match and it immediately returns a result... no more spending hundreds of dollars or waiting in strange offices!
In all, Astrology is an inutile application for determining how well two people will get along, based on the positions of some stars during the month they were born.