With the imminent release of Windows 7, GoG might want to look into creating Windows 7 themes to be included with their games as extras.
As an example, I've created an Evil Genius theme with sliding wallpapers that gets changed every 30 minutes.
This didn't take me more than 5 minutes to do, but it would be more convenient if Gog had done this and perhaps included some sounds and custom window colors.
I can share this theme I've created, but I've not done so now, as you cannot download the wallpapers anywhere else except through gog extras, so I'd need the go ahead from a moderator before sharing it :)
I just think it would be a nice extra to have from gog, that wouldn't take much time, and quicker gets you "in the mood" for the specific game you've downloaded.

you'll probably have to wait until gog officially supports win 7
also, post this in the 'features wishlist' thread.

Sounds neat - I'd probably use one if they were doing this for some of the games in the GOG collection.