Toys: puzzles and food dispensers
Puzzles and food dispensers are one way to keep a dogs' mind active and prevent boredom behavior. There are lots of puzzles and dispensers to buy, many you can make and use at home. The homemade ones can sometimes be as much or more fun than those you purchase.
Websites: with games for dogs. -- Dog Play -- Dogtime --
Book: Beyond Fetch, filled with fun, interactive activities, by D Caroline Colie, Ph.D