So i own some games id like to play with some friends.. and since we will only play the games together for like one weekend i was wondering... if they download and install the game via my account and i do the same.. will the games comflict in multiplayer ?

i know this might be seen as illegal but it is really only one weekend ...( Trial - demo anyone ) ?

It is illegal. From GOG's FAQ, question 9:

9. Can I enjoy my purchases both on my laptop and desktop computer at home?
Yes. We do not limit the number of installations or reinstallations, as long as you install your purchased games on computers in your household. So yeah, if you've got a render-farm in the basement, you might actually break the world record for the number of legal Witcher installations in one household. However, if you think about installing your game on a friend's machine or sharing it with others then please don't do it, okay?
The same principle applies to movies - you're free to watch them anywhere you want, with anyone you want, as long as you don't share them with people who haven't purchased them.

Emphasis on the bolded text.

Some of the games require a multiplayer key (you'll find it in your account), so it probably won't work with these.

Basically, this is the one thing GOG asks us not to do. Therefore, I won't help you do it.

Of course, you're free to do whatever you want, legal or not. But coming to the GOG forums to ask for help on this... not cool.

It´ll work and is OK as long as the games are using some form of LAN-Multiplayer and you are doing a lan at your home. Otherwise: Don´t do it!
(Download the game via your account is senceless anyways...)

Downloading via his account points to them being too far away to just pass on directly (i.e. not at his house).

we are doing some BBQ in my summerhouse and want to play together . it is just some classmates and we dont do this normally so thats why it is only for this weekend :)

so no i am no pirate or have intentions of breaking lawwwzzz

The thing is, you are asking if it's OK by GOG. I'm telling you that it's not OK. If you still wish to do it, that's your choice.

Actually, he's asking if it would work. He doesn't seem to care about whether or not it's OK by GOG, he already made up his mind on that front. Maybe he also wants a moral seal of approval from the GOG forum, but that's secondary.

Other than letting him know that GOG officially doesn't approve of this, and that therefore we won't help, there's nothing more to be said. Yes you do. You've been told of the situation, if you still intend to go against it, you DO have intentions of (consciously) breaking lawwwzzz. Do whatever you want, but do it while taking responsibility for it.

Depends on the laws of your country. In Germany it would be legal.

The way I read this, it means it's okay - so long as it follows the other rules. Exchange "watch" with "play" and there you have it. Assuming, of course, that I'm not missing some blurb about only one instance of the game running at a time on that server farm.

Just make sure they don't leave with installers nor installed games. As long as the multiplayer is over LAN, you shouldn't have (much) trouble setting things up.
In theory this could be construed as a shitty thing to do, but as long as you don't make a habit out of this - go for it. There isn't really anything to gain by abstaining, other than a misguided sense of superiority.
Be sure to mention GOG to them, BTW. They might like it here...

GOG explictly asks (with a please) not to install your games on a friend's machine. We're talking simultaneous installs on other people's machines here, I'd say it's pretty clear. I'm not going to say I consider this an absolute rule to guide my life by, but I do find it quite distateful to ask on GOGs own forums for help to bypass that.

I assume you've read the other post and know that it is illegal, and not ok by GOG.

That said, I don't know what game(s) you want a play but I assume that you're spending money on food and drinks if your friend stay for the weekend, or maybe your friend are paying their part. Games are pretty cheap here on GOG and there is a sale right now so why don't you consider opening GOG account for your friends and either buy them or have them buy the games? The price of the weekend's drinks and food will probably dwarf the price of the games.

I haven't been to a lan party in a long time but we always had our own licensed games or played games that included the possibility of installing a non-standalone version on other computers. (Warcraft maybe?) I do not know of any crime or misdemeanor that are ok if you only do it for one weekend.

The possibility of you facing criminal or civil charges is probably nil if you go ahead and violate GOG's term, so in the end we can only hope that you have a conscience to follow.

If your friend(s) like gaming, why not get them to make an account and gift them a game? Who knows? This gaming weekend doesn't have to be the last! Plus, it gives you a fuzzy feeling when you give a game to someone else and support DRM free gaming :)