Ottawa is considered a wonderful, family oriented city.  The variety of parks, museums and activities provide a multitude of things to do for kids of all ages.

Museums

First on the list must be the Canadian Museum of Civilization, exploring the people that call Canada home.  For the younger set (1-10 yrs), check out the Canadian Children's Museum (included with your admission) where youngsters can explore different cultures and modes of transportation.  And, if you're there during the summer, there's also an outdoor exhibit, where kids can jump into the cockpit of a floatplane.  Older kids will be more likely to appreciate the main museums' exhibits, and may also be interested by the Canadian Postal Museum (also included with your admission).  The Canadian Museum of Civilization is immediately across the Ottawa River from the Parliament Buildings, in Gatineau, Quebec.

The Canadian War Museum is the newcomer to the captial.  Older kids in particular will enjoy seeing first hand actual tanks, bombers and weapons that have been the tools of Canadian soldiers defending our freedom for over a century.

Indoor Activities

Sometimes kids just need to be kids and run around.  While not necessarily convenient for most tourists focussed on downtown attractions, these indoor playgrounds may be just the ticket for a rainy day:

Cosmic Adventures - Ottawa's largest indoor playground.  It's on Ogilvie Road in the east end (Queensway east to St. Laurent, right on Ogilvie, After about 3km, Cosmic is on your left) 

Place d'Orleans Mini Port - located in the east-end Place d'Orleans Shopping Centre - this small playground includes a drop off program for older kids (Queensway east then Highway 174 east to Place d'Orleans Blvd)

Bayshore Shopping Centre Port Pizzazz - located in the west end Shopping Centre - another small playground exclusively as a drop off for older kids (Queensway west to Bayshore Drive) 

Wave Pools - The city of Ottawa operates two wave pools: Splash Wave Pool is east of downtown on Ogilvie Road just past Cosmic Adventures (Queensway east, continue on highway 174 east, exit Blair Road north, then right on Ogilvie); the Kanata Leisure Centre is west of downtown (Queensway west, exit Castlefrank south, then left on Aird Place)    

Outdoor Activities

The National Capital Region has an excellent network of bicycle trails.  You can even rent bikes at Rent-A-Bike in the heart of downtown. 

In winter, be sure to consider taking a skate down the world's longest skating rink - the Rideau Canal.  It's usually open January - early March, and there are skate rental options available right on the canal. 

There's also a great number of ski hills just a short drive north of the capital.  One of the most popular is Mont Cascades, which also offers a large waterside complex for cooling down on hot summer days.