Is it possible to completely go into fullscreen? I have hidden everything except the top header with the menus. Is there a way to hide that? Would scripting this require a lot of work ? 

Edit: 
 thanks for the reply. It still leaves the top header with the menus.alt + f9 hides the bottom '''footer'''. Isn't there a button for hiding the top one? Would scripting of that be complicated ?

Edit2: here's what i would like to hide in the 3d view
ALT F10 = something somebody already thought of. Repeat ALT F10 to exit fullscreen mode.

This is what I get with mouse over default 3D layout ...



...and as Sambler says once more with F11 and even the Blender bar is hidden.