[Brian Michell]

My short answer would be to get everybody involved as soon as possible. Find activities that can relate to the students interests, such as writing pseudo code for a simple game and then have them actually act out the code. For some new students they ask "What can this club do for me?" in their minds. If they don't see a benefit for it they will walk away before build season. Just keep in mind that things are good in moderation and not burn everybody, including yourself, out with activities.