Oh you lucky people. I have already bestowed one free game upon you today but I thought this could not go without a mention.
Presumably to celebrate the fact that you can now pre-order Borderlands 2 through Steam, Valve are letting folk have a bash at the original for free this weekend. That’s a whole weekend of Borderlands fun to be had for the price of installing steam and downloading the game. That is a price I am willing to pay.
If you’re wanting to continue past Sunday night then you can grab the game for cheap as it’s also on sale for the duration.