GOG has a nifty sale for the next 7 days that allows you to choose 5 games from this list of 20 and save 80% off their normal prices.
http://www.gog.com/pick_5
Witcher: Enhanced Edition
Legend of Grimrock
Chronicles of Riddick: Assault on Dark Athena
Alan Wake's American Nightmare
Alan Wake
Divinity 2: Developer's Cut
Inquisitor
Deponia
Back to the Future: The Game
A New Beginning - Final Cut
Sam & Max Beyond Time and Space
Sam & Max Save the World
Tiny and Big: Grandpa's Leftovers
Capsized
Defender's Quest
Puddle
King’s Bounty: Crossworlds GOTY
PID
Runaway 3: A Twist of Fate
Lucius
http://www.gog.com/pick_5