Vancouver is a perfect town for family travel. There are plenty of parks, and outdoor life for kids to watch and participate in. 

Stanley Park:   This has everything for kids - waterpark with little water spouts, totem poles, Vancouver Aquarium, Children's Farmyard, Miniature Train, beaches, heated Second Beach Pool, Traffic School, Vista Point where they can watch the Lions Gate Bridge and all the cars going across it.  Plenty of places to eat lunch inside the park.  Kids can bike or rollerblade all around the famous seawall.  Admission to Stanley Park is free, but there is a fee to park there.  In addtion to that, attractions like the Vancouver Aquarium, Children's Farmyard, Miniature Train, Second Beach Pool, and Traffic School do charge admission fees.  

Capilano Suspension Bridge:   This is in North Vancouver technically, but it's an easy 1/2 hour drive from downtown Vancouver.  This is a suspension bridge over a canyon.  Kids will really like the excitment of walking across this bridge over Capilano Canyon.  There is a nice, flat hiking path around the bridge.  Adult entrance fee is $28 CAD (including tax). 

Lynn Canyon Suspension Bridge:   If families are looking for a free suspension bridge experience, they can go to Lynn Canyon in North Vancouver.  Not only is there a suspension bridge, but also an Ecology Centre that houses educational displays.  It is pleasant to hike in the beautiful temperate rainforests of Lynn Headwaters Regional Park.  Lynn Canyon is accessible by public transportation.  From downtown, catch the SeaBus, and connect to Bus #229.   Hiking trails connect to the Lower Seymour Conservation Reserve  where families can enjoy a gentle stroll around Rice Lake or a more challenging hike down to the Seymour River and back.  The  Seymour Valley Trailway offers 10km (6.2 mi) of paved pathway for cyclists, runners, stroller-pushers and in-line skaters to explore, with benches and picnic spots along the way.  NB : No dogs allowed in parts of the LSCR.

Grouse Mountain: This is in North Vancouver close to the Capilano Canyon suspension bridge. The day consists of a cable car ride to the top of the mountain that takes about 8 minutes and gives spectacular views of  Vancouver and the surrounding area. The trip to the top of the mountain is about $32 CAD (including tax) for an adult.  Tthis includes everything at the top too. There is a bear sanctuary, a bird of prey show and an amusing lumberjack show for all the family to enjoy. You can also go parascending for an extra fee. There are a couple of restaurants and the usual gift shop, etc. The view from the top of the mountain on a clear day is amazing. More to do here than at Capilano. To get here use the SeaBus to cross Burrard Inlet, then connect to Bus #236.  A day pass on the public transport system is $8 CAD for an adult and is worth the money. The SeaBus is fun for kids too. 

Granville Island:   This is a busy outdoor market area that older kids would enjoy.  It can get too busy and confusing to toddlers.  Granville Island was originally just a sandbar that was filled in to create an industial centre in the heart of the city.  By the 1970's it had fallen on hard times and the federal government took over it and developed it into the immensely popular mixed use space that is it today.  Although best known for the public market, it has many theatres, artist studios and there are still several industrial tenants including a cement factory.  When planning a visit, keep in mind that it's really not an island, there is a filled in causeway so it's possible to drive, bike or walk onto the island.  

Summers and weekends are the busiest times but even then you can avoid the parking hassles by arriving early or later in the day; arriving anytime after 4 pm usually means plenty of parking and still lots of time to do things.  Parking on the island is free, usually for three hours but there are some one hour zones close to the Market and the Net Loft Building.  If you don't want the hassle of finding free parking or you want to stay longer than three hours then there are also several pay parking buildings that charge $11 CAD a day.  Most locals don't even realize this, but you can park anywhere you want on the island from 7 pm to 7 am free, even in the pay parking lots.  If you don't feel like driving to the island, there are several other family friendly ways to access it.  Granville island is serviced by two excellent water taxi companies: Granville Island Ferries and The Aquabus. Both of these run several routes but the most popular and frequent trips run from the island right across the water to downtown.  Both of these ferry companies run this route about every five minutes and charge about $2 CAD one way.  The trip is a blast, especially for kids, and they allow strollers on board although you need to fold them up and take your children out of them for the crossing.  From the downtown side, you are within a relatively easy walk to many downtown hotels or you can always hop a bus.

Science World is a favourite with children.  There are many hands-on displays that make this a very user-friendly museum.     

Queen Elizabeth Park:   Located to the south of downtown at the highest point in the City of Vancouver, Queen Elizabeth Park offers lovely views of the downtown skyline.  It used to be a quarry and they decided to turn the big hole into a sunken garden.  Kids would like the little waterfall and bridge in the sunken garden.  Admission to Queen Elizabeth Park is free, although there is an admission charge for Bloedel Floral Conservatory, which is located in the park. 

Find Family Fun is a website created by a Vancouver family with three children.  It contains excellent descriptions of landmarks and attractions, including the age groups to which they appeal.  You can sort attractions by price range, by geographic location, and by the authors' preferences.   

Maplewood Farm  in North Vancouver is a favourite with young children & families who adore animals.  Once a thriving dairy farm, the 5-acre site has since been taken over by the District of North Vancouver and opened to the public in 1975.  It now houses over 200 domestic animals and birds.  Watch for special events like the fall fair, sheep shearing, pony rides and Hallowe'en and Christmas displays.  Located 10 minutes from downtown Vancouver near Iron Workers Memorial (Second Narrows) bridge, off Dollarton Rd.

Tourism Vancouver has a dedicated section on their website listing suitable activities for families.