Bicycling for 30 minutes nonstop will give you a great cardiovascular workout while affording you options you never knew you had. You can bike through your neighborhood or to your favorite destinations, such as the library, park, or grocery store. If you want to avoid traffic and bike on a paved, level trail, check out the Rails-to-Trails Conservancy website to look for bike paths in your area. Biking is a great activity when you're looking to have fun with your family and get cardio exercise at the same time.
Step it up:
Keep extending your bike route by 2 to 4 miles every week. Find a location you want to visit. Ride to your destination and back. You'll get a great workout, and see new things.