Mario Tennis is an instant classic.

User Rating: 8.5 | Mario Tennis: Power Tour GBA
Mario Tennis is pretty fun. I started playing this game 3 months ago. (The main reason I started playing it was my PSP wasn't working, and we didn't have internet at the moment.) The story of this game is pretty simple. Nothing dramatic happens. I think that anyone would only play this game because of the gameplay. After I got internet, I still coudln't stop playing it. There are a lot of mini-games. It took me about 50 hours to complete everything. (One reason this happened is because after you beat a mini-game, you gain exp. for a certain muscle. Those mini-games were HARD in Master mode.) I loved just trying out all the powershots. Eventually, after beating a star character mario in master mode, I went back to the story and entered the peach cup. It was easy compared to going against mario one-on-one. I juat love the game.
All this is my opinion. You might hate the game, and I will respect that.