Indoor kids' activities in Seattle

If your kids like to be active  Arena Sports - Magnuson located at Magnuson Park in Sand Point north of down town Seattle. They have a fun zone with lots of activities. Lynnwood Bowl & Skate is great fun where you can rollerskating and/or bowl. 

Oooooh, I love Seattle!  I've never taken children around up there before, but I can think of a few places that might be good:

• Pike Place Market is the most obvious one.  Tons to see there.  You can see the flying fish, grab FRESH mini donuts at the  Daily Dozen Donut Co, look at toys and comic books at  Golden Age Collectibles Ltd. 
  
• Close to Pike Place is the  Seattle Waterfront.  Lots of cool stuff there like an  Ivar's Acres of Clams, which is a local chain of seafood restaurants that I dig, and  Ye Olde Curiosity Shop, which has the bomb homemade fudge.
• Pacific Science Center is pretty cool if your kids are into science.  Don't know how old your kids are, but there are also sections just for toddlers.
• Go to the top of the  Space Needle.  Just the trip up alone is cool enough, then you've got the view from the top!
• If your kids are into planes, you should go to the  Museum of Flight (duh, Boeing's up there!).
• The most obvious one would be the  Seattle Children's Museum.
• Another fun thing to do would be take the  Duck Boat Tours.  Take a stroll on land, then in water!

Good luck with those kiddos and have fun! :)

First-- it won't rain a lot.  It will likely be gray, and might well drizzle, but Seattle gets less rain annually than New York City.  So I'd suggest bringing a light rain coat and getting out there!

For indoor activities that are kid friendly, I'd recommend:

• Seattle Aquarium - right on the water.  Right nearby is Ye Olde Curiosity Shop, which is amusing.
  
• Museum of Pop Culture - amazing looking building with a lot of interactive exhibits inside of the kids are old enough to enjoy music.  There's also a nice/geeky sci-fi museum in the same building.  This is right near the Space Needle, which won't be a ton of fun for kids (for the dollar) but gives you a nice view of the city.
  
• Woodland Park Zoo is a pretty solid zoo if the kids enjoy animals and you get a day with some nice weather.
  
• Museum of Flight is one of the standbys that local parents rely on.
  
• A water taxi ride across elliot bay to West Seattle lands you at a great little hawaiian/korean fusion food place and is a fun/very cheap boat ride with indoor/warm seats. http://www.kingcounty.gov/transportation/kcdot/WaterTaxi/WSeattle.aspx ..  Once over there, you can do a long walk to Alki Beach Park which is a nice beach with good restaurants.

The Seattle Aquarium is great for younger kids (we took my 1.5, 3.5, and 6.5 year old kids there all the time when we lived in Seattle). The Pacific Science Center center will be good for slightly older kids, and the Museum of Pop Culture may be interesting for them as well. A ferry ride is usually fun for all—take the short ferry ride from downtown over to West Seattle's Alki Beach Park and enjoy the view and the beach. The Museum of History & Industry (MOHAI) was a favorite of ours as well, and they had some good stuff for kids, too (though maybe more on the younger side). 

The Pacific Science Center is a great place for kids of all ages and could keep them busy for a few days. But don't be afraid of outdoor activities such as "Ride the Ducks of Seattle" or a baseball game at Safeco Field (or a tour of Safeco if the Mariners are on the road). Woodland Park Zoo is great too. Bring umbrellas and rain jackets in case of rain, and enjoy the beauty of outdoor Seattle that you might otherwise miss.

Museum of History & Industry (MOHAI) has programming for younger children, and is very interactive and interesting for all ages. 

PlayDate SEA is newer to the scene and is a great space for letting younger kids release some energy. 

A lot of the activities mentioned above are included in the Seattle Citypass:

http://www.citypass.com/seattle

It's totally worth it.

I agree on Pacific Science Center for kids of all ages. There's tons to do there & it's at the Seattle Center, so you can easily go to the Museum of Pop Culture(EMP) or Space Needle afterwards.  

Also the The Seattle Great Wheel is all enclosed gondolas, while a little on the pricey side, can be a nice breather and few minutes to sit down and relax.

Kids seem to love Ride the Ducks of Seattle, so I'd definitely recommend that. Make sure to get the "quackers" for them too :)

If you get a sunny day (likely), check out Gasworks Park Marina and bring a kite. There's a great hill there that's tons of fun to fly a kite on.