MacBook Air awakes in the night (when a sleep)? Just curious, i have a old USB mouse connected to my MacBook Air. I noticed that in the middle of the night (when the cover is closed an MBA is a sleep). The LED (red) inside the mouse is turned on for a few minutes (the mouse has transparent case, so thats easy to spot).  I don't hear the fan, but certainly MBA puts some power on the USB port. After a few minutes is goes off again. I think it repeats a few times a night.

Anyone has a clue what goes on?
If your MBA is in Power Nap mode it will perform functions. 

Some of them might activate the USB mouse.

If it bothers you disable the power nap.