You may or may not be aware that in the Asian market there is a game loosely based on Counter-Strike 1.6 called Counter-Strike Online.
The game is entirely free to play but is funded via a micro-payment system which is powered by a custom version of the Steam back-end.
The game is entirely developed and published by Nexon Corporation with oversight from Valve as the license holder.
Recently, Nexon announced that they are releasing a sequel to the game based on the Source engine. It is unknown at this point whether they will be licensing Counter-Strike: Source or Counter-Strike: Global Offensive, but once more the game will be exclusive to Asian markets and released under the same terms as the original.
For now, if you want to see some footage of Counter-Strike Online check out the video below: