They want people to test their servers, so, before you go full retard and redeem your key without reading:

You should redeem your code in the 20-minute redemption window at gog.com/redeem[3] between 2pm and 2:20pm GMT

2pm GMT (and the start of the redemption window) is:
7am PDT (U.S. West Coast)
10am EDT (U.S. East Coast)
3pm BST (London)
4pm CEST (Paris/Berlin)
5pm MSK (Moscow)
11pm JST (Tokyo)
12am AES (Sydney)

http://www.reddit.com/r/patientgamers/comments/35xmua/hey_rpatientgamers_were_giving_away_8k_copies_of/