What should we do in Seattle?

If any of them are into flying and a bit of history, the Museum of Flight Aviation is very interesting when you go with someone who knows and can tell you what you are seeing.  Although you said no museums, this one might be of interest to a bunch of guys/boys.

What are your dates?

skip the needle...the view is available for free !! in addition to museum of flight, try museum of history and industry by lake union...or go to the boeing plant tour in everett. maybe go swimming at madison park--this is just east of downtown, again, on public bus routes..buy a picnic at grocery store..big park and you swim in lake washington...and eat in the neat small neighborhood places.
, drive down to mt rainier or snoqualmie pass and go hiking. I also would endorse Experience music project and the science fiction museum. underground tour may or may not appeal to them. Ft casey and whidbey island can be interesting. take flashlights. you can actually take buses to mulketio ferry, then take free buses up the island to ft casey. it is a fort from the 1890's..great views and small exhibits in light house. nearby are blockhouses built in 1850's to protect local population from native americans. coupeville is a cute small town nearby

you could be full of adventure and take a sailplane flight from lake union.

Dh just returned from a trip there...and what he is telling everyone about is that he "Rode the Duck"...and gave his duck call to our granddaughter...

www.ridetheducksofseattle.com/

don't know if link will work....

I don't think the Great Wheel is worth the money. You'll get better views from the Space Needle. I wouldn't bother going up the SN if it's rainy/cloudy or hazy. You won't see much unless it's a clear day.

I think at those ages your boys would probably like the "ducks" tour. They are the boats that go on the water and land. They give you a good history of Seattle. It's cheesy but fun, IMO.

The Chihuly glass garden is pricey but beautiful. Maybe something just for mom to do when they maybe go to the Music Experience (which is right near each other).

The underground tour is cool. Not sure if they have a kids version for the public. I went with DS on a field trip and we got a "clean" version of the tour. I've heard the regular tour talks about the seedier sides of Seattle.

Bainbridge ferry has the best views of Seattle. You can walk on as a passenger too. I think there's stuff to walk to.

The original Starbucks is on the same street as Pike Place Markeet.

That's all I can think of off hand. Have fun!

ETA: I missed your DD in your post. She'd probably like most of what I posted about. She'll probably be grumpy about some things. She will definitely be bored at Pacific Science Center. Personally my kids got tired of it around 11-12. They'd also been a few times. We did the Boeing tour when DD was in 5th grade and she was bored, least favorite place while I thought it was great!

Pikes street market.... there is something for everybody there. 

Go to the Air Force base and say hi to my son!! LOL

I have never been to Seattle so no advice from me except to go to the original Starbucks (if that is your thing)..

ride the duck boat!

Where's Pennyring when you need her? Did she make it over? I haven't seen her yet.

I agree with the others: the market (first Starbucks, gum wall, theater sports), EMP and the waterfront are great ideas. Take a ferry ride, especially if you're already at the waterfront. Gas Works park and Fremont would be a fun day (cute stores, great restaurants, Theo's chocolate tour in Fremont). Madison park is great too. Your dd would probably like the shops there, same with downtown Kirkland (across lake Washington).

If you're into nature at all you should try a hike. It's so beautiful here it would be a shame to miss out.

Thanks, OP and all responders. I am due in your spring next year- jumping off place for an Alaska cruise! This response will mark my place, I hope.

ETA: due to be in Seattle...duh

I did not like Seattle (the sun came out once in four days!), but at the market, they actually let US catch the fish! Ask when you're there, they may let one of y'all!

What is the weather like in early October? It would during DS's fall break which is the 2nd week of October.

When I visit a new place, I always like to try some kind of food that the area is known for. I want to recommend Pike Place Chowder for clam chowder. They are in the market in Post Alley closer to the Sur la Table side. They make the BEST clam chowder. OK, maybe that's my opinion (I eat a lot of clam chowder!) Go and tell me if you agree