Valle de Bravo lives in the realm of Mexican myth and legend. It's not a big resort town, but it occupies a place in the Mexcian imagination like Cancun, Acapulco and Cuernavaca. Part of that is because it's superseded Cuernavaca at some point as the Mexico City getaway. It later lost that distinction in absolute terms, but it's held on to a distinction as both cities have jockeyed for the honor over the many years since then.
Originally called Pameje, the town was founded in 1530. But during the colonial period it was known as San Francisco del Valle de Temascaltepec. Temascaltepec starts to clue the observant reader into the fact that this was long a place of temazcales, that is, the ancient version of a sauna or spa. It was only in 1878 that the State of Mexico renamed it in honor of General Nicolás Bravo. He was an Independence movement figure who went on to serve as president on three separate occasions between 1839 and 1846. In the late 1930s, the country's massive electrification and hydrology works projects graced the region with a giant dam that became responsible for the giant lake we see today.
The landscape around the lake later became the setting for a number of auto races in the late 1960s. Later it drew attention from musical festival organizers during the 1970s heyday of musical festivals. And since then, it's simply grown as a major site for weekends away from Mexico City and Toluca.
For some reason, lack of geographical knowledge likely being most important, Valle de Bravo always seems further away than it is. One hour west of Toluca, that means it's only really two hours west of Mexico City (in admittedly Utopian traffic).
Both Zina and Wayak run regular buses from the Observatorio station in Mexico City. To avoid the most serious traffic, take the Tren Insurgente to Toluca, and walk 15 minutes north to the Toluca Bus Station. A taxi will do the trip in 4 minutes. The trip from Toluca is still about an hour, but at least you're not sitting in Mexico City's infamous pre-weekend, exodus traffic.