In Spiral Rider, you have to control the fish and get it to the middle of the spiral to meet its friend Chris the Crab. This is the first game in Scratch Programming in Easy Steps, so it's quite simple, but it does show how you can use the pen together with movement to create a game, and the game itself can be quite tricky. It's hard to avoid catching the fish's tail on the spiral as you go around a corner! Use arrow keys or touch the fish to change direction: the fish moves all the time.
This is an example from the 2nd Edition of the book Scratch Programming in Easy Steps by Sean McManus. More info here: http://www.sean.co.uk/books/scratch-programming-in-easy-steps/index.shtm
