Jon,
How about a snorkel trip to Molokini off Maui?
We've dived all sides of Molokini several times and
it's sensational, but we have also done the snorkel
trip with non-divers, inside the protected lagoon of
Molokini crater, and it's pretty damn good.
A thick "skin" or, 3 mm wetsuit, (probably rentalable
from fading memory), would not hurt as the big Pacific
is cold. Worth the half day, imo.
GL,mD
http://www.mauisnorkeling.net/snorkeltrips.html
Not humping this outfit; just one of many I found in a
quickie web search.