We went to 50's Prime Time Diner in Dec. of 2006 and Dec. 2007. In 2006, we had the most AWESOME waiter. He totally got into the act and involved us to the point that we were laughing so hard we were almost in tears.

Since our experience was so great, we had to do it again last year. It was NOT the same.

Our waiter only made a few comments about "no elbows on the table" and that was it. The atmosphere is fun, but it's a luck of the draw as to whether or not you'll get a server that is truly fun. I was highly disappointed last year, and also embarrassed as I had reallly pumped up the fact that this place was such a hoot. The group we were with last year, thought I was nuts as there wasn't anything funny about our meal experience.
We tried Whispering Canyon Cafe last year for the first time. Again I felt kinda dumb as I had read so many reviews about how fun it is there and pumped everyone up again. People on the boards raved about how the servers get you involved and make jokes and such. Again like the 50's diner, we didn't have any luck. We simply ordered and ate our food. No "hooplah" at all. Our kids tried to take part in the stick horse races, but by the time they reached the box to get a horse, they were all gone.

It was disappointing from a "get involved" aspect. It was great food though.
I would recommend either of them for their atmosphere, but if you're looking for fun and games, I wouldn't count on either of them. Like I said above, it's pure luck

of the draw as to whether or not you get a great server.
For better food I would go to the Whispering Canyon Cafe.