oh hell, I was thinking about buying the civ games that are on sale, but with a summer sale so close should I hold off and hope they hit the same discount and get them in the sale and earn points to get a free copy of a game I already own?

No. And during the last sale, there wasn't such a "collect points to get a free game" system.

Moreover (correct me if I'm wrong) games are often bundled during big sales, which means you need to buy more games to get a full discount. For separate title it may be better to buy it now.

That wasn't the case during the last sale, although it has been that way in several earlier ones. In the last sale they just had "collections", which were a bunch of games gathered on one page by some kind of theme. They were sold for the same price as elsewhere on the store and with the same discount whether you bought just one or the lot. Some people complained about that, but then again, some other people complained about having to buy games they don't want to get the best deal in previous sales. The last sale was thus very straight forward; just lots of games available at discounted prices. It seems GOG is still experimenting, so it'll be interesting to see what they'll do next.

They will probably get the same discount (75%) in all sales they are involved in from now on. It's the standard discount on Steam too which happens like every two months on average.

But why do you want to get a free copy of a game you already own?

No Weekly Sale announced today. It seems that this afternoon we're starting something bigger (:

Or tomorrow, after the discount of the Bethesda games ends.

Oh Well played GOG, made me pay the price for waiting by raising Australian prices just hours before the sale started.

Bravo

That's not nice. But I was also right. The discount (in percent) is exactly the same. However, that doesn't help you.

What's going on?
I received notification and a lot of titles is discounted, but there is no official announcement...

Yes! The discounted games filter shows 7 pages of games. There are a lot of games at 75%+ off.
Lichdom Battlemage is 95%

Folks appear to think it was a test for an upcoming sale:

https://www.gog.com/forum/general/the_unannounced_gog_promo_thread/post270

I would rather say it's some kind of false start.

It's time for big sale, when you look at past schedules. There were always big sales in September (2014, 2015). Last year was different with Back to School sale in October, but it was definitely late, because it ended just before the Fall Sale started.

I suppose it's the last moment for some bigger sale. In other case it would collide with Fall Sale.

Since the first Witcher released on 26. of October 2007, my prediction is:

"10th Anniversary Sale" from 26th til the 31th of October :D

Nice guess, but I'd rather expect some kind of Halloween Sale for that period.

By the way, we're starting interesting part of the year. There will be probably two big seasonal sales during next 2-3 months (Fall Sale at the beginning of November and Winter Sale starting usually at the beginning of December).