Something I accidentally discovered is that in Windows 8.1 (and probably 8 as well – and Windows 7) you can use the Windows key + a number to open an application from your task bar!
So lets say you’ve got Google Chrome at position 1, Thunderbird at 2 and Visual Studio 2012 at position 3. To open Thunderbird simply press Windows key + 2. For the other applications use their position number.
Useful? I don’t know, but it’s nice to know this shortcut exists to keep your hand away from your mouse I guess.