A Modding Marvel
It seems some people who are more knowledgeableand capable than I had the same gripes about Valve’s B.S. Since November of 2004 (that’s right, since HL:Source was released), a team of 
developers not at all affiliated with Valve has been hard atwork creating Black Mesa: Source. They are currently about 50% of the way through recreating a digital world from the ground up. From maps to models to music, these guys are advertising a finished product that practically rivals HL2 itself. And their efforts have not gone unnoticed; for the second year in a row, they’ve won the Best Upcoming Mod of the Year and are enjoying unbridled support from the online modding community. They are actually no longer even accepting applications for modeling since they have so many volunteers onboard.
Now here comes the best part about Black Mesa; it is a 100% free mod. That’s right, this amazing source mod will be released for free download once it’s finished: not the beta version, not a trial version, but the entire game. But realize that this is only a possibility because of the efforts of the gaming community. All too many times, projects such as this one have only made it halfway through development because their teams have just run out of time and money (let’s not forget about Goldeneye: source). So if you’re digging what they’re working on, by all means, support these guys!
Black Mesa currently has a page of community projects up on their website. They’re asking for help with real-world advertisement, concept art, and skinning vending machine food. So my advice is this: when you’re checking out their website and discovering just how good this mod is, check out their community page and see what you can do to help. I’m sure you will all agree that it is definitely worth your time to ensure that this mod makes it to its release.
Check out their website as well as their trailer on Mod DB