Also try your cruises' roll call. On Boards, scroll down until you find Roll Calls, then search for your cruise by line, ship, date. It's actually very easy to do. If there is a roll call already set up, there may be excursions (outside of the ship's excursions) already set up. If nothing else, you may get ideas.
The Ports of Call board is also an excellent source, as Capriccio said.