"Firmly sticking to the Half Life 2 formula, Deep Down is a new entry in the story of Alyx and Gordon as they continue the hunt for Combine Advisors in the area surrounding White Forest.

Combine Forces, Zombies and Antlions lay between them and the brooding menace deep below the earth that will test both their skills further than ever before.

If you miss the Half Life 2 formula and are tired of waiting patiently for Episode 3 then this mod is for you. Featuring new gameplay elements, fiendish puzzles and blistering action, Deep Down will provide your Half Life 2 fix (well some of it at least).
"

Whereas I am not as crazy about Half-Life 3 as some, I am more than ready for it. Even if Valve just said "hey you know we are like 3 years out on it" I would be happy. Just to know people are working on it and the game is coming.

But, since we can't get that right now Deep Down looks like the next best thing :D

http://www.moddb.com/mods/half-life-2-deep-down