Interesting, Gabe Newell over at Valve posted on Reddit that they are working on a new single player game. He also mentioned that there is a possibility within the Half-life and Portal segment to see some new games.

Everybody is still hoping for Half-Life 3, but that question remains unanswered. Valve will keep using their Source Engine 2 game render engine for the games as foundation for the unannounced games. below a recap of the answers:

Hello Mr. Newell,

What is the status of Half Life 3/Half Life 2 Episode 3?

• The number 3 must not be said

Is Valve still working on any fully-fledged single player games?

• Yes

An unidentified anonymous source at Valve has said that Half Life 3 has been cancelled. Is that source legitimate?

• I personally believe all unidentified anonymous sources on the Internet.

How many people are now working on CS:GO? The community is frustrated at the lack of updates and the fact that most of the bugs haven't been fixed.

• 20-30. Same as always.

How long will it be until Valve adds CS:GO servers in other parts of the world (such as Russia)?

• We're adding servers all the time.

Valve is working on a new single player game