It should be in September - as I count correctly. Will GOG team prepare sth special for this occasion? GOG leave BETA status, big promos, contests, LucasArts games added to catalog ? :-)

GOG leaves beta - possibly
Big promos - Definitely
Contests - See previous
LucasArts - Its just GOG reaching 2, not hell freezing over

Sure as hell we get some GotYs releases here. For the big anniversary it's likely to happen.
We should start saving guys. The big fun is comming.

If Hell freezes over on Lucasarts' arrival, what about EA?

Maybe a "Buy 1, get 1 free" promo, this time with more than just Interplay titles?

That probably will cause 'The big bang' or armageddon.

Update 2.

Uhh, seeing so many high expectations make me fear there will be rage and riot if GOG can't pleasure them. Three weeks to go, so just relax ;-)

Hmm, maybe this time we'll have to give GOG something (as is customary on birthdays)? Say, for one week, every game will be $5 more... :-D Or we just have a large cake baked for them (which will NOT be a lie!). (Anyone from Poland knows the GOG HQ's location personally?)
Or, if we take GOG as a whole, complete with us, the users, we'll celebrate by giving each other gifts ;-).

Maybe we'll get TWO games that week? ;-)

If there are any new publishers at all it would be a coincidence. I highly doubt GOG would jerk around a new publisher just to make their birthday more special.
Most likely would be a fair sized sale.

Actually, after further consideration, I'd have to say the site update/end of beta would be the most likely birthday event. I'm sure there will be a sale or promo of some kind to go along with it, but the past statements GOG has made regarding the "GOG 1.0 update" would seem to indicate they have been planning it to happen sometime soon.

That would be when pigs start flying ;-)

its going to be a deal with either rockstar games or ea or 2k games

Swine already flew.