Johnson Space Center Membership Question

I grew up in Houston so I've already done pretty much all the "touristy" stuff as a kid. However, I'm hosting an out of town visitor in April and one of the things I wanted to take her to was NASA.

Does anyone have a membership there? Adult single visit admission is $29.95/ea., but a yearly dual admission includes 2 tickets/visit and is $90 for the year but includes parking and other perks included.

I was wondering in the extra price is worth it.

Also, any other suggestions for where you take out-of-town visitors. I live in Midtown/Montrose.