I always though Mario Chess would make a great game. Not a video game, but an actual chess set.
As Meowrik said, the Mario sports games cannot be games that require large teams. Henceforth, two good ideas in my mind as Mario Bowling and Mario Billiards (Yes, billiards. Think about it.)
Of course, I am STILL eagerly awaiting the release of Mario Jai Alai. The thrill of hitting Peach in the face with a ball launched at 160+mph is worth the $50.
Stupid Quotes: (10th Edition)
"Super Mario Sunshine is an overhyped, boring kids` game with a fruity name that got higher ratings than it deserved."
"Aaron S." - with a dishonorable mention to Electronic Gaming Monthly magazine (Issue #165, pg. 24) for printing the opinions of people who don`t deserve to have opinions.