Dink Smallwood (RPG) & Darwinia

http://www.rtsoft.com/dink/

It has a modding community, and easily loadable player-made modulules that make this thing..potentially massive.

It'd funny,
and creepy in some parts...

It has attitude, and it's free.
You might consider convinging them to start charging for it,
to get some profit, whatever you want...
but please include this game, it's a treasure.
A relatively unknown treasure.

http://www.dinknetwork.com/ (modding community)

+The RPG: NOX
(from westwood.)

Darwinia:
I was a fan of this when it was unknown,
If you can secure the rights to sell it, or even have a link to it (no harm in it)
then it would a be a good addition.
It's currently distributed with 'steam' but many people don't use that service at all,
having it here would naturally be a good thing because of this.

"The world of Darwinia is a virtual themepark, running entirely inside a computer network and populated by a sentient evolving life form called the Darwinians. Unfortunately Darwinia has been overrun by a computer virus which has multiplied out of control. Your task is to destroy the Viral Infection and save the Darwinians from extinction."

http://www.darwinia.co.uk/

There's a box distribution of Darwinia as well.

I saw it at the store today. Looks fancy!

Introversion was one of the first companies we contacted, actually. But their deal with Valve is apparently exclusive.