Penny likes to run and jump. However, sometimes I'm not sure how much exercise is good for her. Therefore I was interested to read an article called Fitness in your backyard. It gives a general overview of what kind of exercise is suitable for the average dog and how you could manage this in your local environment.
I found the article by following a link from a great Squidoo called Canine Athletes! by JohannTheDog. The Squidoo has lots of interesting information about a great variety of sports and athletic activities for dog.
If you haven't already visited Squidoo, it's worth a visit. It's a community of sites where anyone can set up a site to teach a skill or share a passion. Tonight there were 848 sites (called 'lenses') for the search word dog and 199 for canine.