We went May '02.
I booked in advance over the phone (pprox 30 days out).
By doing this we saved $. ($5 per person? Don't recall now.)
It was fun, but wasn't what I expected. It was more of an entertainment/musical. I was expecting more of an interactive murder mystery dinner.
Food was better than we expected. Although we arrived and ate at opening, and food was barely warm. It was good, but not hot.
Warning: If you get there early, they have guests wait in the small and extremely smokey bar section. It smelled terrible. Wait in the hall!