Ubuntu Shortcuts

Alt + f1	Open main menu.Use up/down/right/left arrow keys to select in Applications/Places/System.
Alt + f2	Run Application.This will bring up a window,type command to run an application.
Print Screen	Make a screenshot of whole screen.
Alt + Print Screen	Make a screenshot of current window.

Window Shortcuts :

Alt + f4	Close the current window.
Alt + f5	Returns window to 'normal' or previous size.
Alt + f7	Moves the current window
Alt + f8	Resizes current window
Ctrl + Alt + Del	This will minimize all windows and apps,and bring you to desktop.
Alt + f9	Minimize the current window.
Alt + f10	Maximize the current window.
Alt + Tab	Switch in windows.

System Shortcuts :

Ctrl + Alt + Delete	Restart the computer immediately, without saving open files.
Ctrl + Alt + Backspace	Restart X Windows
Ctrl + Alt + Plus	Rotate through supported screen resolutions
Ctrl + Alt + Minus	Rotate backwards through supported screen resolutions
Ctrl + Alt + F1---F5	Open Virtual Terminal
Ctrl + Alt + F7	Return to Graphics screen from Virtual Terminal