Rarest game owned? I believe some trade stimulators are games.
This is an original (except for some interior springs) 1932 Exhibit Supply Company ‘Spel-it’ dice game. Takes cents through quarters and you need to spell your winnings. Shown is a big win TW E N TY, where the operator needs to pay out x20 the last coin played (in little window). Also gives gum balls.
This game is shown on some of Exhibits lists of games made, but left off of most. Not found in any of the trade stimulator books to my knowledge either. Only one online I can find is the one I bought, shown here. Experts I’ve talked to haven’t seen it, so, pretty rare I think.