Brazos Bend State Park

This place is kind of unique for me, but is still one dimensional. You can see gators in many places in SE Texas, but there are a ton of them here. And if you're a bird watcher (I'm not) this is also a hot spot for you.

But, like I mention, that's all it is. A series of trails around several ponds and a channel connecting them, fairly full of alligators.

You should probably go, especially if you have kids, but take bikes so you can get around and see the whole place easily. Walking would be fairly boring, and even the kids will get tired of alligator after alligator. And don't take the dogs. Several alligators wait at the edge of the water, facing land, and would most likely pounce on them. Yes, I'm serious.

There is an observatory here as well, but I'd say your time was better spent driving all the way out to the Davis Mountains to see the McDonald Observatory. Go here for a fairly close day of something different. Its main benefit is that it's close to home for me, so I don't watse too much time on the road. But again, take the kids and bikes and it's at least something different to do for half a day.