If you're looking for something fun and active to do with your family, I have just the suggestion.
The kids and I just did the Color Run this morning in Washington, DC. If you haven't heard of The Color Run, it's an awesome "fun run" that's called "The Happiest 5K on the planet". It comes to cities all over the U.S. (and it looks like it might be headed to Australia too!) As you run (or walk) along the course, you pass through several "color zones where you're hit with colored powder. At the finish line, everyone has a packet of colored powder they get to throw as part of a color festival! We definitely had a blast (as you can see from the pictures) and I'd totally recommend it as a fun activity for families.
(NOTE: The colored powder might be a bit too much for really young children, but my school-aged kids had a blast)
Check it out...
Like I said, I'd totally recommend it if your kids are school-aged (or go with other adults as a fun day out if your kids are too young). The Color Runs do tend to sell out pretty far in advance, so check the website to see if it's coming to a city near you.