Aero Peek is a new feature in Windows 7. If you have many windows open on your desktop, its quite easy to lose track of them.
Aero Peak lets you ‘peak’ behind all the windows so that you can have a look at your desktop, should you wish to access any gadgets or shortcuts. It does so by making all the open windows go transperant. To do so, you simply have to move your cursor to the extreme right part of your taskbar and hold it there. Or else click Win+Space.
If you press on that panel, all the open windows get minimized and your desktop is shown.
With Aero Peak, you can also choose to preview any particular open window, while hiding all the others.
To do so, move your cursor to the taskbar button whic you want to preview. A taskbar preview, ie a small windows will appear. Move your mouse ove this small taskbar preview.
You will see all the open windows, except this one, get hidden.