Something everyone should try to see if ever near the Grand Coulee Dam is the Summer Laser Light Show on the face of the dam.
http://www.grandcouleedam.com/aboutlls.html
They spill a thin stream of water across the width of the damn and then start an amazing light show.
One could also make a great vacation out of it if you like to camp and stay at either Sun Lakes or Steamboat Rock State Park.

What other hidden treasures are out there?

They did Pink Floyd's The Wall laser light show off of the face when I was in high school ... that was freakin' amazing. I wouldn't recommend camping at Sun Lakes though, unless you like lots of college kids drinking it up with orgies happening all around you. That woke THIS 15-year old up!

Grand Coulee Dam is great to check out overall, you can spend an entire day there going through the different parts, the tunnels down to the generators, the visitors center of course ... they have a tram on the backside, it's really cool.

If you go in the summer, I hope you like heat. It's bloody hot there!

I think Sun Lakes has changed since then, at least maybe the resort side and not the public campground was pretty darn nice. I would like to stay in one of the rental homes right on the lake sometime, one with it's own dock. That would be cool.

If you get over this way, you can visit the "Unemployed Broadcasters Memorial Fence"
This hand built 120 foot tribute is open to the public year round. Bring a laser pointer, and create your own special light show, and chase the squirrels as well. Furnished one bedroom lodging on premises, as well as a primitive campsite for the adventurous. View dozens of bird species and take in the sights of a variety of wildlife.

Below is a testimonial from one of our guests.

"So where's the mall?"

;-)

Do we have to get out of the car to enjoy it? Is there a paved walkway to it?

I also have a discount coupon for the World's Biggest Ball of Mud that's nearby. Will you honor that as well?

Hopefully we can all caravan in Edsel's Airstream.