One nice feature of Knights Chess is that it supports Portable Game Notation (PGN). So it can view the multitude of chess files out there.
PGN Archives:
FloridaNurse
Chessopolis
BritBase
PGN Mentor
Charlotte Chess
Chess World
Chess Club
Tactics – Loiodice
Openings
MyChessSite
PGN Links:
PGN Specification
PGN Specification
Javascript PGN Player
PGN Utilities