They built canals and irrigation. They had homes, jewlery and dishes. It's amazing that when they left, they left behind a majority of their belongings. Miners who came to the area, found all of these things just as they left them.
Some believe the Hohokam completely died off, though based on the Hohokam name origination, it is believed the local Pima and Papago tribes are the decendents of the ancient tribes.
Read more about them on Wikipedia or visit the Cave Creek Museum.