Fremont Peak Observatory

To be honest, the view from the observatory out towards the valley, with the fog layer sitting below you like the biggest bowl of whipped cream known to man was just about as cool as the observatory. That alone was well worth it.
The observatory too was neat. We happened to be campng there the night of the month they open it up. There was a nice video presenation (nothing you would not see on the discorvery channel but cool never the less), a QA with the on site volunteer and then they let the guests look through the various telescopes which were focused on the moons of Jupiter. They have one big honkin (about the size of a VW Bug) telescope but the volunteers also had about ½ dozen (6 if you must) other telescopes set up as well, so the kids were able to take a little more time on those. For anyone into astronomy it would be a must. Probably pretty entertaining for almost any 7 to 11 year old kid.
Side note, the drive up has some sharp turns. My mothe rmade it up with a trailer on her truck but it was a bit hairy. The camp ground there is usable, but nothing too special. It was dry when we were there so we were not allowed to have a camp fire :(