You got some links for this awesome RTS?

Surprised I haven't seen this one yet.

Ancient Domains of Mystery

Extensive Rogue-like. Think Nethack on steroids. Has Mac betas, Linux, Windows, and DOS versions available.

Is mudah still around?

He hasn't updated the list in a loooooooooong time.

One of my favorite "old" PC games Star Control 2 went open source and is now being made into a superior version. Dont be afraid of the Beta tag, its a soldi release with very few bugs. They just never got around to adding in the extras they wanted to. They still managed to merge the voice and animation from the 3DO version, however.

I suggest trying it, its quite fun.

Oh shit, people are actually still posting in this? I had only noticed the new posts today, believe it or not. Sorry guys, I'll get updating. If I've missed your game along the line yell at me over PMs or something and I'll add it in.

e: List finally updated.

Combat Arms

Saw this one on the back of PC Gamer and decided to check it out. It's actually a really good FPS, the graphics are great for a free game, and the community isn't all 10 year olds.

Samurai of Legend
 

Found this one as a banner ad. It's a decent game and similar in the way that Kingdom of Loathing plays. It allows you to get married, get a job, buy a house, adventure, kill things. I find it fun. Anyway here is the link!

Samurai of Legend

As you can tell it takes place in the days of samurai, it's very fun!

Gang Garrison 2

It's basically a 2D version of Team Fortress 2. It's a really fun online game and I'm really blown away at how things are implemented for just a 2D online shooter. I'd personally recommend downloading the latest version as (despite what it says) I have the least amount of server issues and you can do a whole lot more.

It's still under development though (Engineers are unable to make Sentry guns right now if I remember correctly), but loads of fun.

Are there any freeware Flight Sims that don't blow ass out there? I've been googlin' my eyes out for weeks, thought maybe you people Up Nort' might know of anything. Not looking for ZOMGMSFSX or anything, just somethin' I can bum around on while my PS2 is on the fritz.

Also, yes, combat related. Not terribly interested in puttering around in a Cessna for hours.

Infocom has the three Original Zork text adventure games for download for free.

Also while I've seen ADOM and Nethack mentioned I have yet to see anyone mention:
Moria (warning: this game is no longer maintained) or
Angband or any of its Variants
These games are available for windows(except for moria), Linux or Mac.

P.S. Diablo was based of the Rogue/Moria/Angband tree, not the Hack/Nethack tree :P