We only had a few hours at the Anthropology museum, and I could have easily spent an entire day there. We totally ran out of time, and basically had to choose between the Anthropology Museum and the Contemporary Art Museum in Chapultepec Park. Of course on our way out we also noticed that there was a fun park filled with midway rides as well. Plus that huge concert venue.
We did managed to pack in an incredible amount in our extended long weekend in Mexico City, but if I were to do it again, much more City and much less Cancun Resort. The diving was pretty good, but I got really squirrelly basically trapped on a resort for week. It just don't feel "real" to me.