Windjammers is an odd game, being something of a mix between fighting games and sports games. The combination may sound rough, but it works really well, surprisingly! The game has more to it than it seems at a glance.
There are twelve characters (Biaggi is my goat) as well as a hidden unlockable character, all of which have either more strength or more speed to varying degrees. The variation may seem imperceptible, but it actually really helps each character feel unique, even if their normal moves are the same. Every character also has unique specials. In addition, there's a wide variety of stages, each having their own unique scoring system, adding further variety.
In short, Windjammers is simple on the surface with a fair amount of depth for anyone willing to try to learn. The online is rather sparse, unfortunately, which may dissuade folks from picking it up, but even then its still a good game to pop in with a friend for a little while.