Dungeons and Data Science, or D&D.Sci, is a series of analytical exercises played on Less Wrong, frequently framed as problems in a D&D style adventuring world.

D&D.Sci exercises give players a synthetic dataset but not the rules used to generate it: players must extrapolate patterns from the data in order to optimize the solution to some problem. After each exercise there is usually a follow-up post which explains the underlying rules of the scenario and gives a score to each player who participated at the time.