Groupees' Shiny Loot 6 Bundle is another 'build-your own' affair, allowing you to pick two games for a Dollar (c. 58p) and add extras. In this case, I'd recommend grabbing Escape Goat and Hacker Evolution Untold, both of which I can personally recommend as being well worth the price.
However, there are two things to note. First of all, you'll have to create an account on Shiny Loot to redeem your bundle keys, which is a bit cheeky. To ease the sting, though, you'll probably get a free copy of Really Big Sky for your trouble once they sell over 2000 bundles. UPDATE: Full credit to jaystan @ HUKD, who found this before I did!