If you do not want to use the summer to be sunburned or eaten by mosquitos, and in stead doing some brain sit-ups you can visit Microsoft’s “Join The Tech Elite” webpage.
Here you have collection on knowledge in the form of links to Technet, webcast, downloads and much more. One or more of the topics covered will most likely be something for you. It is connected to the Microsoft Virtual Academy, and there are even a quiz competition J
Topics are Azure, Phone, Windows 8 development, Windows 8 deployment, Azure IAAS, Private Cloud, Windows Server and Visual Studio
So have a educational summer