"The Park in the Park"
Petco Park, home of the San Diego Padres

This is the small park behind the main stadium
where kids can hit a ball, run the bases and pretend they're playing ball
just like the major leaguers next door.
The surrounding area is used as the cheapest seats (I think $5-6) in the ballpark.
Views are not the best of course but you are there.
Just bring your blanket and a picnic basket.

Those are hotels, parking garages and condos going up in the background
...and the neighborhood just keeps changing...