I did some searching on the message boards, and it looks like the 2000-rated girl is the toughest opponent on Wii Sports tennis and that's why we are put against her over and over again after getting high in the pro skill levels. Getting your rating over 2000 is very tough, and getting it up to 2400 is impossible, from what people have posted. Somewhere in the 2300's, there is a point where no more skill points are awarded even for a perfect match against
the top computer opponent (perfect=winning every point).
In other Wii Sports news, here's a guy who uses Wii Sports to lose weight (he has a funny youtube video):
some mainstream media coverage of wii weightloss guy:
Here's a guy who figured how to put on weight while playing Wii sports ;-)
Some emerging Wii problems are "Wii elbow" and broken straps from people throwing the controls:
Here is somebody's video of a perfect 300 game in Wii Sports Bowling.