Here is a 1960s era trading pamphlet on NYMEX potato futures, once the core contract of the exchange. It was mentioned in The Asylum that the May contract was legendary as the primary deliver month and would have enough volatility that Chicago traders would fly to NYMEX just to trade it for a month.
Ultimately, the potato contract was delisted w/a default and control of the potato market was wrestled by J.R. Simplot to his Idaho environs.
As always, click on the photo to enlarge.