I would like to weigh in on Knoebel's.  My wife and I visited there for
about a half day on the way to the MBSI meetings last August.  We spent
a total of $5.50 for our rides on the carousels, Ferris wheel (which
went for well over 15 minutes) and the nickelodeon.

Parking is free and there is a tram that takes you to the amusement
area.  You can bring your own food.  There is no entrance fee.  Ride
tickets can be purchased in two ways: (1) per-ride tickets, or (2) an
all-day pass.  There is a large swimming pool.  Cabins are available
for rent.  Food there is good and inexpensive.

One of the carousels has four or five organs and they switch from
one to another from time to time.  The other carousel has one organ.
There is a large steam tractor, which is basically used to run a small
sawmill while you watch.  There is a small carousel museum.  An outdoor
amphitheater announces the performances by a very large simulated 18-note
music box.

We were greatly impressed by the whole place, its rides, its prices,
friendly and helpful staff, office personnel (whom we visited to tell
them how much we appreciated what they had to offer).  We picked up
a stack of brochures and have given them out to many of our friends.
My wife and I agree with the others who have mentioned this place.
Make it a priority for any travels to eastern Pennsylvania.

Vincent Morgan, New York City