You've already had a look at the auction and chat implementation in the ICEfaces examples. These examples are pretty cool and also present realistic use cases. The book example should follow this idea. But the aim was to create something fresh and new, and not just a poor copy of the existing stuff.
The basic idea is a mixture between Battleship® and Risk®. But instead of "Ships," we have invisibly-allocated countries to hit. And the "Army" of a country can be beaten immediately by naming the country.
Each player has five allocated ...