1.Wife and I went to the Mayan Riviera (flew into Cancun) for our honeymoon, resort was absolutely gorgeous, off of it looked like what you would expect Mexico to look, somewhat rundown, but not terrible.
2.We stayed in the Casitas suites with our own mini pool which connected to a lazy river out to a pool complex for our set of rooms, it was sweet. I believe the name of the property was El Dorado Royale, or Royale with Cheese or something like that. Had a couple of friends go about a year later and they loved it as well.
3.Went in June=Hot as balls, looked at winter, but it was much more expensive, and didn't completely work with our schedules, but we would have liked to go then.
- Went snorkeling, wifey didn't get certed in time, so we just settled on snorkling. Being open water certified and switching to snorkling sucked because the guides were constantly bitching at me to stick with the group, but following a pair of rays and a couple of turtles that the rest of the group didn't even see, just 20 feet away from us was well worth being threatened to be picked up by the boat and ending my snorkel trip prematurely. I believe most reputable shops will want you to be certed, but some do have crash courses, and the place we stayed had scuba clinics, but she wasn't comfortable, so we held off.
There were some skydiving tours that I saw offered. There are tour companies all over the place at the airport, but I would highly suggest you wait until you get to your resort, because we were warned by several sources to just book it there just to be certain they aren't some random dudes ripping off your money/cc info. There were several zipline companies, but we wanted to relax a couple days and not have to worry about doing something constantly, so that would seem like a pretty cool thing to check out during a future visit.
Went on a tour to Playa del Carmen and to Tulum-the Mayan ruins on the ocean, Playa del Carmen was kinda shady, lots of little shops/street dealers but some interesting trinkets to haggle over. Tulum was incredible, a lot of tourists, but our tour group told us when to be back for the bus, so we split off from the guided tour and did our own thing, which made it much better. When we went there we did commit an error that ruined most of the last day of our trip-we ate at a cafe just outside the ruins, didn't drink the water, but had some nachos, and Montezuma had his revenge, so I definately recommend you DO NOT eat anywhere off the resort unless you take something with you.
Found the link for the place we stayed, service was excellent and the food was even better, the gym wasn't terrible, but there was a ton of stuff to do just on the resort grounds, you could spend your whole vacation just on site and not go anywhere else and still have something to do the entire time.