This is a delightful and quite light-hearted LARP scenario that will work equally well with novice or experienced LARPers (even better, a mix of both). It's steampunk in style, which lends itself to some fantastical yet reasonably accessible costuming.
Set at a wedding - between members of two leading dynasties of an alternate 19th century world where steampunk concepts rule, it has actually been playtested at a REAL wedding. It is GM-light, you can get away with just two, and is designed for up to 30 characters, for which character sheets are provided (in both PDF and Word format, so you can edit them if you wish). Interestingly, several characters can be played as either male or female, making it easy to fit the roles to the actual players involved. Some can be even played as cross-dressers, although there's a sensible note that they are not necessarily the best characters if you actually have transgendered players in your game. Consult with all players to ensure the role they are taking on is one that they will be comfortable with.
Requirements for staging and props are quite minimal, although there is scope to go to town with steampunk and period items if you have inclination and capacity.
Rules are minimal too, and designed to mostly be self-moderating with little need for GM involvement. For example, combat may only occur one-on-one and is resolved by a game of rock-paper-scissors. For some items cards are provided to enable players to interact with them on their own.
As for plot: well, there are all manner of interactions built into the characters provided as well as a 'Mad Scientist Resource-Gathering Game' that revolves around deciding what your next Grand Design project is going to be and acquiring the resources and assistance necessary to build it. Some characters are fascinated by tea and there is a story about that to discover. Oh, and at least one person is not who he claims to be and may be found out if the other characters are observant... and several other plot strands as well.
Quite a lot of printing will be involved in setting up this game, and it will be helpful to have at least a few experienced LARPers (or at least role-players) to get things rolling and drive the various plots along. If everyone enters into the spirit of the thing, a magical entertaining session ought to be in store!