Simple wall hanging with driftwood and shells from the beach. Here's how to drill holes in shells: http://www.completely-coastal.com/2010/09/drill-baby-drill-shells-dremel-tool.html
Also on these boards
Sea Shell Wind Chimes - drill holes in assorted shells, cut lengths of natural-colored cord. tie a knot in end, add shell; go to next interval, tie another knot, add another shell - and so on. Finish by tying top of cord to a hook and connect to rafter, ceiling, etc.
Hang tassels off your balloons!