World Championship Games has a nice variety of 14 summer events and includes the ability to play single events or take your turn at either a Tournament or Decathlon. There are also three difficulty levels to choose from, although veterans of these button-mashing (or in this case, stylus-sliding) games may find themselves immediately on the highest setting in order to deliver a challenge, unless something changes between now and release time.
The graphics displayed in World Championship Games are a bit on the basic side, and unfortunately resemble a lot of DS games on the market with their extremely-low polygon characters and environments. However, being that you will be looking at the bottom touch screen more often than the top 3D screen, other than in replays, it isn't all that disturbing.