They have it running on raspberry pi and a tp link router with a plugin usb modem.  It has a battery built in and turns it in to a wifi access point!  The site they go to is piratebox.de to get instructions and potentially link to the items you’d need to buy online.  They have a generic installer and then download the specific firmware for the router you use.  (random note the site looks like it was built using bootstrap which often indicates a tech oriented community, not always)

More transcription from the video would be:

• Install raspbian wheezy which is a linux like install for raspberry pi
• You need to get lighthttpd
• You can ssh using the command line if you like
• Need to install host APD daemon before you have wifi access

Now next time you want to meet at the mall or wherever with other raspberry pi file sharers remember to stay legal and only trade owned licensed products.