All of Cyan's games on Good Old Games are 50% off this weekend.
Uru: Complete Chronicles is now $4.99, the rest of the games are $2.99.
The Manhole: Masterpiece Edition
Myst: Masterpiece Edition
Real Myst
Riven: The Sequel to Myst
Uru: Complete Chronicles
http://www.gog.com/promo/cyan_worlds_2