selecting an item from listbox and using the name of the item later

I'm making a small project using Python 3.4/5 in conjunction with Tkinter. I have make a list box that shows all items in a directory. I can't seem to find a way to select an item and then save the name in a variable for later use.

listnotes = Listbox(notebox, selectmode=SINGLE)
listnotes.pack(side=LEFT, fill=Y, padx=10, pady=10)
listnotes.insert(END, "notes")
for i in glob.glob("TESTFOLDER*.txt"):
    i = i[12:]
    listnotes.insert(END, i)

I have read around that using listnotes.get(ACTIVE) might work. Also i haven't been working with python for all that long, so any insight will be appreciated.