In each of the last two years, there's been exactly one official high school dance, held around April. This time, last year's dance organizers are mostly still students, so we seem on track for another. But reasons for 0 include that planning things is hard, and reasons for 2 (or more) include that maybe there's still additional dance demand (no middle school dances have occurred yet...)

To count, such a dance must be promoted by Proof as an official event. This is regardless of whether all students are invited, or whether non-students are.

General policy for my markets: In the rare event of a conflict between my resolution criteria and the agreed-upon common-sense spirit of the market, I may resolve it according to the market's spirit or N/A, probably after discussion.