We have enjoyed several trips to Cancun... stayed at the Hilton every time except one, and other than taking the bus to the upper end of the hotel zone to look around, shop, etc., we have gone to ruins with tour groups. We enjoy relaxing more than being active or swinging with the night people when there. There are plenty of options though; I imagine the wedding party has included many for you.
Do you know if your hotel will have transportation included... will they be picking you up at the airport?
When you arrive in Cancun, the first stop is Immigration for a passport check; then pick up your bag and go through Customs. They use a random pick (by machine... red light/green light) for those who will have bags searched. Seems to me that more travelers are searched than in other foreign airports.
After Customs the best advice I have is that you not stop to listen or talk with anyone until you are outside the airport in the area where the vans and taxis are waiting to take you to your hotel. As soon as you are on your way past Customs there will be people asking you where you are staying. They will say they have been waiting for you... Cancun's timeshare hawkers. Ignore these people. This includes the "Tourist Information" booths. They are often dressed alike and will seem to be everywhere. Very aggressive!
If you have pre-arranged transportation, they will have told you how to recognize them (outside). I have found this website accurate and useful:
http://www.cancuncare.com/Cancun_Airport/
Immigration will issue you a card (like a short term visa) to carry with you and return at check in as you depart Mexico. It is a good idea not to misplace this card.
You may be given a health survey to fill out as you approach Immigration... it is simple, relating to fever, cold/flu symtoms etc.
This VIOL thread might be of interest also:
http://www.virgin-islands-on-line.com/f ... ht=#192170
I hope you have a wonderful time at the wedding and in Mexico.