A very well-meant thank you for having a forum thread for this giveaway, not just the usual twitter-only deal which makes me feel that gog doesn't care for its own community (as well as personally excluded for not using social media).
I'm not a very creative person, so no pictures or videos from me - but for me, living in the Netherlands, summers feel mostly unpleasant (I vastly prefer spring and autumn). We generally don't get super hot days, but the heat we get is almost always very humid and oppressive, so I tend to sit inside a lot, trying to move as little as possible, and just endure. My PC doesn't have a super powered videocard, so doesn't give off too much heat, and that means that gaming is quite possible.
My best memories and experiences of summer gaming are from the evenings of the hottest day, where the humidity has built up so much that the massive thunderstorms rolling in at the end of the day feel exactly as inevitable as they are. When the rain starts pouring down, I'll throw the doors to the garden wide open to let the house cool down (finally free to do so without the risk of hordes of mosquitoes flying in!), and have the sounds of heavy rain and thunder - and the light effects of the lightning - provide the perfect background atmosphere to any number of games.
I have a particular memory of playing through Old Vizima in the first Witcher on such an evening, and that really working very well. Not certain yet what I'll be playing when the first summer thunderstorm of the coming season will be rolling in, but I have no doubt that I'll find something appropriate. :)