After all the phrases in several discussions about how DRM in multi-player is "okay" or "necessary" even around here, I want to start some action on the topic and make this a regular thing.
What I've done is put together a Discord community for DRM-free gaming. We've got a few members from various servers (mostly GOGlodytes), but I'd like to make the place much bigger and drum up interest. So, to kickstart things, I've decided to hold a competition!

To avoid misunderstandings:
This is to promote DRM-free multi-player and also my Discord server as a hub for that when it comes to match-making and voice chat. Prizes aren't meant to be the sole reason to come there, just a nice icing on the cake.

The rules are simple:
Win against one of the players in a DRM-free multi-player game (number of rounds etc... depends on the game) and win a key of your choice.
The keys are all for games that have DRM-free multi-player.
Voice chat is possible of course.
I am using Linux but have a well configured WINE (2.22-devel with lots of Winetricks) layer by now, am on Central European Time (UTC+1) and available most evenings.
Since I am not a competitive person and don't have the most compatible rig, volunteers as "champions" are very welcome, even more so people who just like to play together (including Co-Op).

In order to enter, you neither need Galaxy, nor any additional account, nor Windows, nor a ton of games in your library since many of the games you can choose from are actually free.

Donations are welcome as long as they implement any kind of DRM-free multi-player (couch co-op counts as well).
I will start with giving away one key each for two players this month (2018-01).

The currently available prizes are:
Descent 2
Oh...Sir!! The Insult Simulator
Star Wars™: Jedi Knight™ II - Jedi Outcast™
Star Wars™: Jedi Knight™ - Jedi Academy™
Titan Quest Anniversary Edition
Unreal Tournament 2004 Editor's Choice Edition (donated by Buttspikes)

Choose an arena from this list:
Hedgewars (free)
http://www.hedgewars.org/
Invisigun Heroes (free guest edition with three characters and a bunch of maps)
https://sombr.itch.io/invisigun-heroes
Mega Man 8-bit Deathmatch (free)
http://cutstuff.net/mm8bdm/
Quake III: Gold
https://www.gog.com/game/quake_iii_gold
https://ioquake3.org/
Scorched3D (free, current Linux version may be hard to install, Windows version also perfectly works via WINE though)
http://scorched3d.co.uk/
Screencheat
http://www.gog.com/game/screencheat
http://www.humblebundle.com/store/search/search/screencheat
Soldat (free)
http://soldat.pl/en/
Unreal Tournament 2004 Editor's Choice Edition
https://www.gog.com/game/unreal_tournament_2004_ece
https://pcgamingwiki.com/wiki/Unreal_Tournament_2004#Install_Native_Linux_version
https://www.gog.com/forum/unreal_series/ut_2004_run_natively_on_64_bit_ubuntu
World of Padman (free)
https://worldofpadman.net/en/
Worms Armageddon
http://www.gog.com/game/worms_armageddon
Xonotic (free)
http://www.xonotic.org/

Suggestions from my other list are possible as well but keep in mind that they'll be invalid if technical problems show up, so the list above is safer.
https://www.gog.com/forum/general/drm_free_multiplatform_multiplayer_games/page1

People are welcome to stick around and stay with the community or otherwise welcome to join even if they aren't interested in the comptetition right now but still interested in DRM-free multi-player in general.

Great idea, very creative way to draw attention some good DRM free multiplayer games. A gladiator in training in the Americas ... hmmm. o.O Not in BTW, the wife and I are co-op team players not duelers, but definitely looking forward to seeing how this goes and the creative challenges it could inspire. Just give us a moment to set up the popcorn stand off to the side here. :D +1

Not in, but your idea is very interesting =)

All Quake3 and Quake engine based game (Open Arena, Nexuiz,QuakeLive) maps are compatible with Warsow.
There are even Counter-Strike maps (which are made for Quake) which can be played on Warsow.
Try [url=https://lvlworld.com/review/id:2231]de_dust2 for quake 3[/url] in Warsow.
It might look cartoonish but it will work!

I'm allergic to MP, so not in, but cool idea for a GA. Good luck to the gladiators.

(You bet he was.)

Same for me, which is why I'm at the lookout for more gladiators participating in this event as a community service (with me hosting the server). I'm not a competitive person but will do it to let people know, that DRM-free multi-player is still a thing. Huh, interesting. I have all those games so not really a need for it but that's a great feature.

Nice idea for a creative giveaway, klumpen! I also like the fact that you chose to use discord. I found one other that was even open-source and with encryption for different platforms, but seems to lost due to lack of interest.

I might chime in for both playing and donation (I guess anything as long as it is drm-free?)

Suggestion of arena: https://renegade-x.com/ (free, from the C&C universe)

Umm,can I use a rocket launcher and elephant?

I found one that was open-source and decentralized but needed so much work to get working that it wasn't really an alternative, which one do you mean? In this particular GA all the prizes contain some kind of DRM-free multi-player, be it directIP, hot-seat, couch-coop or something like that. Master servers are okay as long as they don't need additional accounts or other clients besides the actual game. Oh, an MMO sequel to Command & Conquer: Renegade. I still have that game, never finished it but loved the idea and played it in LAN once a long time ago.
Although the prizes don't have that restriction, all the arenas in my list are multi-platform (even if through WINE) so that everyone can potentially participate.
This one does even seem to work well on non-Windows systems according to WineAppDB:
https://appdb.winehq.org/objectManager.php?sClass=application&iId=13916
Does it need an account or is it possible to just play with buddies outside of the leader-board?

EDIT: The forum was acting up like a troll hiding my answer and I double posted.

Nice GA! Not in for now (and hoping for a CO-OP game, as I am like you said, not too fond of competitive/shooter games)
Hmmm, is 0 AD a valid entry?

Sure, I don't see why not.

Birth of the Empire's has now a multiplayer beta. If anyone wants to spend a couple of hours with a 4x strategy. Get it here: https://drive.google.com/file/d/1o7QaVP_8-PgI-B7ReBsdCtSigDRBDv4D
If there is interest next week I can do a Linux and an Android package aswell :D. Linux users though can simply take the jar and run it if they want to...

Anyway if I'd have time I'd also be tempted to play a Q3 with you guys. Alas I can't in the near future... still cheers and thanks for the great competition/giveaway idea.

Thanks for the hint.
I added both to the pool in the other thread since they also have Platinum rankings in WINE's App-DB and therefore aren't exclusive to Windows users anyway.
https://www.gog.com/forum/general/drm_free_multiplatform_multiplayer_games/page1

https://appdb.winehq.org/objectManager.php?sClass=application&iId=1246
https://appdb.winehq.org/objectManager.php?sClass=application&iId=4456