Since reading Sarah's last post, where she heard that word on the street is that you have to do at least one ship excursion, I have found the page that lists all the excursions and their prices. So up for the voting I think. What sounds best?
Cabo:
$69
Cruise to the Chileno Reef marine sanctuary and experience the fun and adventure of sea kayaking. Begin your adventure from Cabo San Lucas aboard the Adventure, a specially designed 90-foot boat tailored to offer enjoyment for all ages. Cruise for approximately one-hour along the coast passing world class championship golf courses, miles of unspoiled serene beaches, breathtaking landscapes and secluded untouched coves. After arriving at the protected marine park at Chileno Reef, your experienced guide will offer instruction before boarding your two-person “sit-on-top” kayak. Venture out with your guide for the approximately 45-minute kayak from Chileno Reef to Santa Maria Bay passing extravagant rock formations carved by sand, air, and sea. Stop at Santa Maria Bay where you may rest for approximately 30 minutes on the white sandy beach, swim or snorkel. The Adventurer will pick you up in the bay to begin the return voyage to Cabo San Lucas as the friendly crew provides chips and salsa and serves margaritas, beer, and soft drinks.

$19 -cheap and is only 45 minutes long
Travel by boat to view Cabo San Lucas’ famed rock arches, where the Pacific meets the Gulf of California. Your approximately 40-minute boat tour explores Los Arcos, the majestic rock arches where the waters of the Gulf meet the Pacific. Watch for wildlife including pelicans, sea lions and seals as Jean-Michel Cousteau provides taped narration of the area’s ecology and points of interest. Enjoy a complimentary beverage while surveying magnificent views of the coast, Los Arcos, and your Princess ship at anchor.

$49
Your guided kayaking adventure visits the dramatic rock arches at Los Arcos, then you don a mask and snorkel to explore the marine sanctuary at Lover’s Beach. Transfer by water taxi to the kayak launching area, where you receive an orientation on how to kayak and your mask, snorkel and safety vest. Board your two-person sea kayaks and paddle across San Lucas Bay, passing Pelican Rock and circling the dramatic rock arches of Los Arcos. Continue to Lover’s Beach, where the waters of the Pacific and the Gulf of California meet. The offshore waters are part of a marine sanctuary; you have a short time to swim, sunbathe or snorkel. Board your kayak and return to the kayak launching area, where a water taxi transfers you to the tender pier. All snorkeling equipment including safety vest, instruction and supervision, bottled water and transportation are included.

There are about 20 different snorkelling tours, so apparently that's the thing to do there. There is also whale watching and swimming with dolphins!!!

Mazatlan:
As much as I'd love to spend $50 to see a flip-flop factory.... All of the excursions sound awful. But I think the deer island one is the one Sarah and I plan on doing, but on our own (without the blue haired ladies)
$67
Travel to secluded Deer Island for swimming, hiking and a guided kayak trip that is suited for beginners. After a short transfer by taxi, board a catamaran for the 40-minute cruise to Deer Island. Disembark at the beach on the island’s leeward side, where you find chairs, ample shade, bathrooms and changing facilities. Swim or take a guided hike of the island that leads to stunning views of Mazatlan, the coast and the Pacific. After a short safety orientation, board your kayak for a 45-minute guided paddle along the island’s shore. (These simple "sit on top" kayaks do not require prior experience.) Board your catamaran for the return cruise to Mazatlan.

Peurto Vallarta
$99- I really want to do this one!!!! Is rappeling hard?
Explore the jungle canopy of the Sierra Madre by air-sailing from treetop to treetop. Receive a briefing onboard and then drive to a private reserve in the Sierra Madre, where professional guides help you master the techniques of using horizontal traverse cables to travel through the jungle canopy. Glide through the trees 90 feet above the ground along a series of zip lines, jungle bridges and across a Tarzan swing, pausing at special observation platforms in the virgin forest to observe plant and wildlife. At the end of your adventure, rappel 70 feet to the forest floor. SPECIAL NOTES:This active excursion is designed for passengers in top physical condition.


OOO or this one! Price isn't listed
Experience the thrill of discovering the flora and fauna in the jungles of the Sierra Madre. Designed for maximum adventure, this tour takes place in an area of pristine, unspoiled forest where scenic beauty and rich ecological habitats create a true tropical paradise. This active 6-hour excursion brings out the child in all of us. The adventure begins with an off-road adventure when you board a Unimog 4x4 and drive into the heart of the tropical forests where you'll learn a variety of wilderness techniques, ride mules, splash through streams, rappel through waterfalls into natural river pools, and soar 200 feet above the ground over the jungle foliage on a 1000 foot zip line! Our trip leaders' knowledge of the landscape and wildlife makes these trips unforgettable adventures - and their expertise ensures a fun, educational and safe trip into the wilderness. Discover and explore the extraordinary flora and fauna hidden away under the canopy of the jungle.

$69
This one sounds good, but I think it might be the same place that Arnold Scwartzenegger's Predetor was filmed. Others have said to avoid that tourist trap.
Relax on board a modern catamaran as you cruise south of Puerto Vallarta following the spectacular tropical coastline of Banderas Bay. Your journey takes you past some of the most picturesque scenery in Vallarta, where dolphins and humpback whales are often sighted during the winter months.The morning is spent at the tranquil cove of Majahuitas, an unspoiled area of natural beauty on the southern coast of Banderas Bay. Only accessible by sea, Majahuitas is the desert island beach of everyone's dreams. With swaying palms, and a sheltered cove with crystal clear waters which offers ideal conditions for swimming, snorkeling and kayaking.After lunch aboard your catamaran, head off to Yelapa, an old charming Mexican fishing village set in it's own natural cove. Long a famous day trip from Puerto Vallarta, Yelapa has become a must on most tourist's lists, but since there are no roads in, this tropical paradise is only accessible by boat.The tiny village is a true escape from civilization. If you love the outdoors and want to spend time exploring nature, this idyllic spot is perfect for you. Hike through the jungle to the Cola de Caballo waterfalls, swim in the cove's protected waters, or just relax on the expansive sandy beach. As you cruise back to Puerto Vallarta, the on board fiesta wraps up a day full of fun-in-the-sun with an open bar, dancing, music, and entertainment provided by the friendly crew.

So what would you do? Check out the other options at: http://www.princess.com/shorex/index.jsp