With apologies to Morty and Helen Seinfeld.
If you've got to take a rest along Interstate 5 this is the place to do it. Easy on and off the freeway, quiet, always plenty of parking, and the best presentation of California's incredible water system anywhere, accessible to both adults and kids. What's the downside? It's officially only open from 0900-1700 and closed on major holidays. Also, it's a pretty boring geocache. But what else do you have to do while driving the I-5?