Hi Good luck for the meet up.
At our Earth Day Beach Clean up day we had cookies made with the earth day logo on them and we used these as the centre piece and they were loved by the hosts.
We also took along reusable plastic plates and drinks in aluminum cans to share - as the aluminium cans can all be easily recycled. I chose food that had minimal plastic and packaging. We did up a beautiful plate of fruit and cut up vegies to have with dips and made a brownie to share!
Good luck.