#24 - Mario Kart: Double Dash!! (Kudos to Truckosaurus for guessing this)
Put quite simply, Double Dash!! is the go-to game at parties for myself and my friends. I can't think of a single occassion where we've tired of playing this game, as every single time there will be a new outcome or combination we can play as that literally provides weeks worth of fun.
While later entries did one thing or another differently that I could never really take to, DD's double kart mechanic combined with some classically awesome tracks and plenty of game modes meant it was a good time no matter what we did. I never quite understood why Nintendo didn't revisit this mechanic with later games.
Perfect fun and the best kart racer I've ever played. P.S. Snaking ftw.