Here's my idea. How about a sale where you can create your own bundles with the only requirement being the games must have something in common. E.g. a bundle where the games were all released in the same year, or are from the same category like fps or adventure, or have the same theme like horror ! Of course some details will have to be decided by GOG stuff, like which games are eligible for this sale and how many do you need to create a bundle.

I liked the one there was the first summer I started buying here for real:
10 Every day, 2 games came up for voting. The one with more votes after X hours gets > 65% discount and the other < 65%.
20 GOTO 10

Hmmm I wouldn't mind having a mini-game where you had to reconstruct a picture, or you played a round of video poker and if you beat a hand type or better you got a free game. Maybe you'd get a number of chances equal to the dollars you paid? so Spend $15 and get 15 hands for free games? (some skill involved, but not much)

Or maybe where you get tokens, and those tokens can raise a discount level up to 10% higher than it normally is for a single game. How you get the tokens I'm not sure, probably either spending or some undetermined specific attribute they decide on before hand that you can't cheat. Or maybe you get 5 for every game in your cart and you can apply them to your games before checkout. Or maybe get x number of tokens and get a free game! Hmmm... But that's not too different from spend X and get a free game either.

That was Battle of the games promo.

+1 for BASIC pseudo-code ;-)

Agreed, really frustrating sometimes.

I don't know, this one seems a little too ambitious to me. It's certainly creative, and it's good that you're thinking outside of the box here, but there are limits to what GOG can do. I'm not saying it's a bad idea necessarily, but there are logistical problems. Most notably, how would they deal with all of that customer satisfaction?

Nudity. From Commander Video to Geralt, I want to see them all letting it hang out!

Steam has trading cards? Well GoG will have nude trading cards! Collect them all! Buy a discounted game? You get their naked glory!

(Note: Darvond has no idea how the steam trading cards work.)

Genre unlocking sale. There will be games from a specific genre and there have to be sold a certain amount of copies to unlock the next genre. Every hour there will be a set of new games of each ulocked genre.

I think it was a previous one. I'd say it was before '14 and only pairs, never more than two games. Also, the only time I remember Arx Fatalis being discounted :P
But then again, my memory is not the kind of person you would trust xD

The Battle of the Games promo was in July 2012. Well before 2014.

Memory sale:
Like in a game of Memory, the games are lying on the desktop with the backside towards you. If you manage to uncover matching pairs, for examplae games from the same genre or the same series, you`ll get a higher discount on them. The games stay unvovered and the buying of them also give you a discount, but not as high as if you have uncovered a matching pair.
I hope what I wrote is understandable since my english is not perfect. :-)

That seems more like it. I googled it and the results were from 2014 and the images didn't resemble my memories.

But well, I suppose it doesn't really matter. That's the one I have liked the most, plain discounts aside.

This might be controversial, but what about offering to sell some games for about 50-75% off normal price? And, you know, let the offer stay for 2-3 days so people can have a look and decide if they want to buy them?

A bit crazy, I know, but it would be fun, I think.