GOG has some deals that end in 24 hours.
You can get Worms Forts: Under Siege Free until 12/17 as part of a Team 17 weekly promo.
Various Team 17 titles are on sale for the next 24 hours also:
The Escapists: The Walking Dead $9
The Escapists: $6
Worms World Party Remastered $7.49
Worms 2 41.19
Superfrog HD $2
Alien Breed + Tower Assault $1.19
World Rally Fever: Born on the Road $1.19
Ultimate Body Blows $1.19
Plus more deals…