Setting Up Minecraft Night (Servers)?

My situation is that at my college we have game nights, were we usually just play steam games and such. This game night we wanted to play minecraft. My question is, how can I set up a server that allows people who don't have minecraft to play? There's about 7 of us who have accounts. Any Ideas?

p.s Were all playing in the same rooms in one of our computer labs.

Dude minecraft has a built in LAN server. If you are on the school network just open to lan in the options. If that doesn't work use the server.exe and run the server. Place the ip of the network in the server notepad file