diff -r d0570cba3749 Lib/turtledemo/__main__.py
--- a/Lib/turtledemo/__main__.py	Sat Jul 26 19:40:16 2014 -0400
+++ b/Lib/turtledemo/__main__.py	Tue Jul 29 17:56:35 2014 -0400
@@ -3,6 +3,7 @@
 import os
 
 from tkinter import *
+from tkinter import ttk
 from idlelib.Percolator import Percolator
 from idlelib.ColorDelegator import ColorDelegator
 from idlelib.textView import view_file # TextViewer
@@ -12,6 +13,7 @@
 import time
 
 demo_dir = os.path.dirname(os.path.abspath(__file__))
+darwin = sys.platform == 'darwin'
 
 STARTUP = 1
 READY = 2
@@ -21,7 +23,11 @@
 
 menufont = ("Arial", 12, NORMAL)
 btnfont = ("Arial", 12, 'bold')
-txtfont = ('Lucida Console', 8, 'normal')
+txtfont = ['Lucida Console', 8, 'normal']
+
+MINIMUM_FONT_SIZE = 8
+MAXIMUM_FONT_SIZE = 400
+FONT_OPTIONS = [8, 9, 10, 11, 12, 14, 18, 24, 30, 26, 48, 60, 72, 96]
 
 def getExampleEntries():
     return [entry[:-3] for entry in os.listdir(demo_dir) if
@@ -48,6 +54,7 @@
 
         self.mBar = Frame(root, relief=RAISED, borderwidth=2)
         self.ExamplesBtn = self.makeLoadDemoMenu()
+        self.FontBtn = self.makeFontMenu()
         self.OptionsBtn = self.makeHelpMenu()
         self.mBar.grid(row=0, columnspan=4, sticky='news')
 
@@ -102,7 +109,7 @@
         hbar['command'] = text.xview
         hbar.pack(side=BOTTOM, fill=X)
 
-        text['font'] = txtfont
+        text['font'] = tuple(txtfont)
         text['yscrollcommand'] = vbar.set
         text['xscrollcommand'] = hbar.set
         text.pack(side=LEFT, fill=BOTH, expand=1)
@@ -115,7 +122,7 @@
         turtle._Screen._canvas = self._canvas = canvas = turtle.ScrolledCanvas(
                 root, 800, 600, self.canvwidth, self.canvheight)
         canvas.adjustScrolls()
-        canvas._rootwindow.bind('<Configure>', self.onResize)
+        self._makeBindings(canvas._rootwindow)
         canvas._canvas['borderwidth'] = 0
 
         self.screen = _s_ = turtle.Screen()
@@ -124,6 +131,37 @@
         turtle.RawTurtle.screens = [_s_]
         return canvas
 
+    def _makeBindings(self, widget):
+        shortcut = 'Command' if darwin else 'Control'
+        widget.bind('<Configure>', self.onResize)
+        widget.bind_all('<%s-minus>' % shortcut, self._decreaseFont)
+        widget.bind_all('<%s-equal>' % shortcut, self._increaseFont)
+        widget.bind_all('<%s-plus>' % shortcut, self._increaseFont)
+        widget.bind_all('<Control-MouseWheel>', self._updateFontByMouseWheel)
+        widget.bind('<Control-Button-4>', self._increaseFont)
+        widget.bind('<Control-Button-5>', self._decreaseFont)
+
+    def _updateFontByComboBox(self, *args):
+        txtfont[1] = max(int(self.FontBtn.get()), MINIMUM_FONT_SIZE)
+        self.text['font'] = tuple(txtfont)
+        self.FontBtn.set(str(txtfont[1]))
+
+    def _updateFontByMouseWheel(self, event):
+        txtfont[1] = max(txtfont[1] + event.delta // (-1 if darwin else 120),
+                            MINIMUM_FONT_SIZE)
+        self.text['font'] = tuple(txtfont)
+        self.FontBtn.set(str(txtfont[1]))
+
+    def _decreaseFont(self, dummy):
+        txtfont[1] = max(txtfont[1] - 1, MINIMUM_FONT_SIZE)
+        self.text['font'] = tuple(txtfont)
+        self.FontBtn.set(str(txtfont[1]))
+
+    def _increaseFont(self, dummy):
+        txtfont[1] = min(txtfont[1] + 1, MAXIMUM_FONT_SIZE)
+        self.text['font'] = tuple(txtfont)
+        self.FontBtn.set(str(txtfont[1]))
+
     def configGUI(self, menu, start, stop, clear, txt="", color="blue"):
         self.ExamplesBtn.config(state=menu)
 
@@ -178,6 +216,17 @@
         CmdBtn['menu'] = CmdBtn.menu
         return CmdBtn
 
+    def makeFontMenu(self):
+        style = ttk.Style()
+        style.theme_use('clam')
+        combobox = ttk.Combobox(self.mBar, font=menufont, width=4)
+        combobox['values'] = tuple(FONT_OPTIONS)
+        combobox.bind("<<ComboboxSelected>>", self._updateFontByComboBox)
+        combobox.bind("<Return>", self._updateFontByComboBox)
+        combobox.current(0)
+        combobox.pack(side=LEFT, padx='2m')
+        return combobox
+
     def refreshCanvas(self):
         if not self.dirty: return
         self.screen.clear()