Io

Prototypical language - no such thing as a class, instead you create a new object by cloning an existing one.

Objects have "slots" - basically a hash. You assign a new slot with := which will initialize it if it doesn't exist

If an object starts with a Capital letter, then it is a "Type" of object (like a class, but it's not a class OK!) it then gets a "type" slot. If an object starts with a lowercase letter then it's an instance, and it would get their parent's type slot.

e.g.

    Book := Object clone
    Fiction := Book clone
    Fiction slotNames # returns list(type)
    dune := Fiction clone
    dune slotNames # returns list()
    

Lobby Nice little feature which lists all the named objects

Hash's

book := Map clone
book atPut("author", "C.S.Forester")
book atPut("genre", "Fiction")

you can turn maps into objects.. 
CSForesterCategory := book asObject

hornblowerAndTheAtropos := CSForesterCategory clone ...