The major novelty in the upcoming Python 3.4 is the addition of an Enum type. If you've ever written code in C, C#, C++ or Java, you've already encountered enumerations and know what they are. If not, here's how Wikipedia defines them:
[A]n enumerated type (also called enumeration or enum […]) is a data type consisting of a set of named values called elements, members or enumerators of the type. The enumerator names are usually identifiers that behave as constants in the language. A variable that has been declared as having an enumerated type can be assigned any of the enumerators as a value.
It'll all make more sense once we start writing some code, but first there's some preliminary work to do.