Window Farms are a clever way to grow plants inside using recycled materials. There isn't anything revolutionary about whats happening, but it is a well thought out project that you can do at home without any difficulty.
What usually goes on is you have several plastic soda bottles that have been cut open and hung vertically. I think that you drill holes in the bottoms of each soda bottle pot to allow them to drain water into from the top both to the bottom pot.
So you water the top pot and the water trickles down to the bottom pot.
You hang a few of these vertical strings of pots in your window, almost like those hippy beads that you'd hang in a doorway.
Sunlight comes in through the window and makes the plants grow. Hopefully you've planted something like beans or strawberries so you can eat what comes off of them. Growing poison ivy is not recommended but none-the-less possible.
That is about it. The devil is obviously in the details of construction, but its not rocket science. Specifics will vary depending on what shape bottles you are recycling and how big you want them.