Some time ago I implemented a solver for the Stable Marriage problem  in Pharo . Basically, in the stable marriage problem, you have two list of n element: a list of men and a list of women. Each person rank people of the other gender according to its preferences. The stable marriage algorithm finds the best matches between men and women according to all rankings.
It can be installed using:
Metacello newbaseline: ‘StableMarriage’;repository: ‘github://juliendelplanque/StableMarriage/repository‘;load