Excellent work Diem! The earlier that the dates get set the better -both to secure a booking and also to get commitment from people. I reckon you guys probably need a team of about four people. I'll keep chipping in with organisational suggestions if that's ok

Other things to consider:

• Find a volunteer to be a DJ - I'm sure there are many people here who have probably had some experience in this regard - rather than just subjecting everyone else to their own personal tastes in music.
• Consider the financial aspects - if a room has to be hired then there would have to be some sort of entrance fee (like 20 francs). This money would have to be collected - perhaps offer some sort of bonus (or penalty) to encourage people to register and pay early? In other words, make tickets available on the night, but at a higher price. Any excess profit could be put into some sort of fund for subsidisation of another event?
• Accomodation - it would be great if we could also encourage forum members from other parts of the country to join us. If we could locate a venue close to a source of accomodation this might help them out. I've no idea if anyone would actually come and stay overnight, but it might be nice for them to have such an option?

That's all I can think of for the moment.