A set of instructions for creating something, each step of which is a Pattern. A PatternLanguage should have an order to it, at least a typical one. Different subsets of the language might use slightly different orderings. A well-ordered subset that produces a particular result is a generative sequence.
It remains to be seen how sequences will be created for GameDesign. Will they break down into BoardGame, CardGame?, AbstractGame? (and so on), or perhaps TradingGame, WarGame?, RacingGame? (and so on)?
CategorySequence? should have an up to date list of generative sequences under construction.