Its my girlfriends birthday soon, and I was stuck for a gift. She loves detective novels, cheesy detective shows (her favourite is Diagnosis:Murder) and the like, so I booked us a Murder Mystery weekend. Its the very weekend of her birthday too! I’ve never been on a MMW: what can I expect? Are they fun?
My mother and my Aunty went on one of those once. When a man keeled over during dinner (apparently people just drop dead all over the place), my aunty, a nurse at the time, rushed over to give emergency medical attention. I think it seemed odd to her that no one was doing the same.
It was all rather embarrassing apparently.
Cool! I’ve been to two.
Typically, there is some sort of get together at the beginning where the murder happens. Then you’ll be introduced to the actors playing the suspects. Over the weekend there are other get togethers where stuff will happen, and you will also be able to tqalk to the suspects. They still let you have fun without worrying about the mystery. (I think they don’t plant clues someone can take to keep things fair.)
One place had you vote on the solution, the other let you get up and stage and present it. Only three of about 100 attendees did. We wrote a routine making fun of the actors. We were wrong, but it went over so well that the troupe asked for it to use for their next gig. 
Anyhow, it’s great fun and don’t worry too much about getting the answer right.
I’ve actually been a participant / writer in one of these before. Tremendous fun. The more the ‘players’ get into it, we found, the better. And yes, we even had situations in which we changed the ending because the ones the players wrote were better than ours!
I’ve also participated in these. They can be great fun. How much fun varies on how outgoing and “hammy” the participants are – the more the better! Go ahead, be outrageous and silly, it’s all for fun.