First thing we did after arriving in Cancun was drove out to Chichen Itza and I must tell you the drive there is amazing! Nothing but green on both sides of the road and every now and then there are a few little towns.
When we arrive there was quite a line to get in but that's to be expected with the amount of tours available and such.
Between the ticket booths and the actual entrance there's a very handy ATM and a souvenir shop. Inside there are many vendors and be prepared to be offered a trade; your shades for a souvenirs and such. There are many things to explore in different paths its a good thing I printed out a map of the place before arriving, the whole place is amazing.
El Castillo
Templo de los Guerreros
El Caracol