Saw Serendipity 3 as we were walking past Caesers Palace on my daughters 21st birthday 8/27/11. We had always wanted to go to Serendipity in NY and thought we'd go in. Daughter spoke with the hostess, we had a party of 5 and wanted to sit inside. The hostess said about an hour wait, then asked if it was my daughters birthday (she was wearing a tiara), the hostess stepped inside for a minute and came back and said don't go far. We were called for our table about 5 minutes later!
The place is cute inside! The waitress asked my daughters name and they brought her frozen hot chocolate out first with toppings and a candle and the staff announced her birthday and sang to her.
We all wanted frozen hot chocolates or milk shakes so we only ordered appetizers. The frozen hot chocolates are very big and could easily be shared (if we didn't want different flavors). They were very good but around $11 so beware of that. We had potato skins, sliders, onion rings and artichoke dip. The food was all very good.
I'd go back for the frozen hot chocolate or the appetizers.... maybe both!