I know it's a bit old but Minecraft has a 90 minute demo, now your friends can try it out before buying it!
I think it's a good thing because if people wanted to try it they would have to pay 15 euros or pirate it, now they can see if they like it and become addicted etc.
http://www.pcgamer.com/2011/04/19/download-the-minecraft-demoShow it to all your friends and family, help CFUK reach 2000!