Not sure if this is considered as a gaming deal, but O'Reilly has certain gaming ebooks and videos on sale for 50% if you use the discount code "WKGAME". The deal expires July 4th.
Gaming - Save 50% I'm not sure whether or not the link contains some sort of referral, I just copied it from the page I ended up at when I clicked the link in the e-mail.
If you like Dwarf Fortress, I very much recommend the guide on sale. Funny, informative, and there's free lifetime updates for the book which the author has promised to update for future versions. All O'Reilly books are also DRM-free.
If you've been interested in playing
Dwarf Fortress (which is a free extremely detailed sandbox game) but found the learning curve to be too high, this is for you. Even experienced players can find it enjoyable with maybe some new things to learn.