Amber Diceless, based on the Amber series by Roger Zelazny, is the most popular of all diceless roleplaying games. It uses no randomizers in conflict resolution, and many feel that the negotiation between GM and players arising from this gets to the basic meat of roleplaying, and teaches awesomeness. The setting of Amber spans infinite dimensions, but some feel that the true setting comes from interacting with the dozen or so interesting and iconic members of the Amber Royal Family. Amber is perhaps the only roleplaying game that has spawned cons devoted solely to it. It has been going strong for more than 15 years.
Essential web pages for Amber Diceless are: