What do we NEED to do while in Cancun?

Travel Info
My husband and I are going to Cancun next month for a much needed break from our 6 kids!!!! Anything that we just have to do while we are there?

Last time we were there we had a lot of fun renting mopeds and going to the market.

Travel Tips

sounds like you need to eat, drink and be merry while remembering to use your birth control. lol.

Others
I would definitely go visit one of the two popular Mayan ruins:

Tulum - http://www.frommers.com/destinations/tul...

Chichen Itza - http://www.frommers.com/destinations/chi...

The ruins of Tulum are closer to the hotel area and you can usually combine a day trip with some snorkling and a visit to Isla Mujeres

Chitzen Itza is a bus ride that takes longer, but is much bigger and just breath-taking and beautiful.

I have been to both on two different trips, and really enjoyed them.
relax enjoy the sun and sand
With 6 kids at home I'm guessing you don't want to waste a lot of money. If your staying in an all-inclusive great. If in a timeshare or condo, grocery shop at Sam's, Walmart or (take the bus and then a taxi back).
Fun......beach, pool, drinks, nice quiet dinners. Go snorkeling at Puerto Moraltes, a small fishing village. Book the trip through the resort-it includes r/t transp. It's a 1/2 trip that you will love!! If nothing else go to Margarittaville for dinner and drinks. They put on a little show and you'll have a great time. We've been down there 6 times and those are the best. Isla Murejes was nice too! Read a book, hand at the beach and make it to happy hour! Enjoy, you two deserve it!
go to the chichanitza and the go to the yucatan area...also don't forget to eat dinner at Perico's!!! it;s a fun place and good food!
Take the day trip from Cancun to Isla Mujeres. For $52 per person they take you across and back by boat (5 miles each way) then you can either take the golf cart tour of the whole island, go snorkeling, or just lay on the beach. You're also fed a buffet style lunch at their private beach restaurant. All is included in the $52 p/p.

I snorkeled once we got there, had lunch, then went on the golf cart tour. The scenery is amazing! I highly recommend it.
I went last month