As an island, it should come as no surprise that Bocas' activities revolve around the water. Snorkeling, scuba diving and surfing are all good here, though by far the most popular activity is just to laze out in the sun. It's a pretty chill atmosphere, so don't be concerned if you find that sunbathing is consuming the bulk of your days. Think of your time in Bocas as a break from the activity-heavy lifestyle that backpacking normally entails.
Michael Karanicolas is awesome.