Left4dead 1 and 2 currently 75% off on Steam.

They are also selling them as a combined Bundle for £5.74, which is a real bargain for loads of co-op Zombie killing action.

And if anyone is feeling like getting friends involved there is also a 4 pack available, so you can then hand out licenses to 3 of your friends for some 4 player co-op gaming.

X Superbox

But even better at the moment is the X Superbox. This contains every game and expansion in the X series for just £9.99. So if you like your space trading and combat here is the chance to buy one of the greatest series in one bundle.

And although I do already own most of the games in this series separately I decided to grab this so I have them all ready to go in Steam, with patches etc more easily available.