Had dinner at Cascal in Mountain View a few times recently. I think you'd classify it as pan-Latin tapas. The main tapas selection is not so great--the city definitely has better tapas. I had a queso fundido that was too cheesy. I also had a sopes--the meat was wonderfully tender, but it was ruined by a hard and stale-tasting fried plantain base.
Still, the appetizer sampler has some very interesting selections, like a date pate with goat cheese, and perfectly seasoned Serrano Ham so thin sliced that it practically melts in your mouth.
By far the best part though is the restaurant's ambience. It's breezy, with wide windows from which you can watch people stroll by. The inside has vibrantly rich ochre and red painted walls that bring to mind old world Havana. And there is always live guitar every night--the guitarist plays some great flamenco. Sexy but carefree is a good description of the atmosphere.
The drinks are good and keep with the breezy atmosphere-I had a virgin mango mint margarita.
It's a bit on the noisy side, given the large seating capacity, high ceilings and exposed kitchen. If you go try to sit away from the guitarist, because the microphone can be turned up too loud at times. The crowd is a good mix of people--some young Silicon Valley professionals, some students, and some families. It could be a good date OR family restaurant.
All in all I'd definitely go back. It was a fun experience.