Bundle Stars' Inferno Bundle is great raw value, offering ten games for a paltry £2.99 over the next five days. However, I'm not entirely convinced that quality matches the quantity.
I can personally vouch for Urban Trial Freestyle and Orbital Gear being rather fun, and have heard some good things about 8BitBoy. The rest, though, will need to be taken on faith - or just sit uninstalled in your Steam library, forever. Thanks to Rubisco @ HUKD!