I stumbled on a good deal today...
OKC<->Cozumel round trip air (continental) + 6 nights at hotel cozumel and resort - breakfast buffet daily (I've had it - it's a good breakfast).
374 ppdo
August 5th (wednesday departure) - 11th (tuesday night arrival home ~10pm touchdown in okc)
If you want all inclusive (3 meals + snacks + bar) 469.00 ppdo
doesn't include diving - but cmon - for 400 bucks for a 6 night stay - wow.
orbitz.com - use promocode "entertain200"
when using orbitz I advise....
put in dates/location - search for hotel/air packages.
When results come in - ignore "best values" (a joke in my opinion), hit the tab for "lowest price" - this sorts by price. Put in promocode above...the prices will NOT update - however, when you select a package by clicking on it - it will udpate the price - it's 200.00 off (or 100.00 off per person in a double occupancy booking).
I've stayed at the resort before - it's nice - it's not 5 star (it's a 3 star place, 2.5 if you wanted to be ultra critical) but it's plenty nice enough for a vacation focused on scuba diving. I wouldn't take my 10 y.o. daughter there for a week and expect her to be entertained every second.
I'm actually going back there next week - leaving wednesday.

lucky me.
At any rate - this is a nice deal.