Here you'll find the rules of some traditional abstract games alongside some excellent modern ones. Most of them (and eventually all of them) can be played in the Pit, and free downloadable applets are provided to store the games offline.

XiangqitraditionalChinese Chess
Congoinvented byDemian Freeling
Chess960invented byRobert James Fischer
Crodainvented byLjuban Dedic
Pilareinvented byJorge Gómez Arrausi
Focusinvented bySid Sackson
Explocusinvented byMartin Medema
Othellocontested by mr. Lewis Waterman and John W. Mollet Esq.
Gonnectinvented byJoão Pedro Neto
Lines of Actioninvented byClaude Soucie
Breakthrough 2invented byDan Troyka
Penteinvented byGary Gabrel
Amazonsinvented byWalter Zamkauskas
Ordoinvented byDieter Stein
FanoronatraditionalMadagascar's National Game
MorabarabatraditionalSouth Africa's National Game (well ... almost)
Nine Men's MorristraditionalWidely known as Mills, Mühle, Jeu du Moulin, Molenspel.

All applets are by Ed van Zon.