Scuba club poster ideas ?

Hey, I'm in the high school scuba club. We're gonna have this year's first meeting sometime soon, and I was just wondering if yous guys had any ideas on cool qoutes, ideas, etc.. to put on the posters that we're gonna hang around school. We want as many people as possible to show up!! Its mainly been only a handful of people in the past (5 or 6 people) but now most of them have graduated.. so we need looooots of people to show up!!
we get really low rates on certifications, and discounts at the shops.

Any ideas on posters, or just ideas on the club in general are greatly welcomed.
THANKS!!!!
Matt