I'm stuck in full screen in the node editor. Escape isn't working, and I have no menus and no idea how to leave except to quit Blender and reopen the program.
To toggle out of full screen area (what I think you did) press AltF10, or move your mouse to the top right corner and click the button that appears.
Here I start in full screen area, notice the button that appears in the top right corner.
If you just maximized the window you can get back to the normal view a number of ways.
- Click the "Back To Previous" button in the info window at the top.
- Press CtrlUp Arrow
- Press CtrlDown Arrow
- Press ShiftSpace
If you toggled blender into full screen view press AltF11.
Update For blender 2.8 the shortcuts are
⎈ Ctrl + Spacebar to toggle maximize
⎈ Ctrl + ⎇ Alt + Spacebar to toggle Full Screen.