How can I power multiple raspberry pi around the house?
I installed a non POE outdoor camera at a location on our property that doesn't have easy access to an outlet. The solution I came up with was to run the camera via POE with a POE to USB Splitter. A quick web shopping outlet search led me to these:

 

They are pretty cheap, and come in a variety of configurations / flavors. I opted for removable USB female adapter, but there are versions that have built in Micro USB plugs.

My Setup: 

Indoors [Wall outlet -> POE Injector] -> 50 ft Cat 6 Ethernet Cable -> [POE Spliter -> Micro USB Cable -> Camera] Outdoor (in Plastic Project Box)

I could see this easily being implemented using a POE Switch, and routing Ethernet to where needed.