KLM is offering a set amount of free lounge passes to the KLM Crowne Lounge in Amsterdam when you book your KLM flight via KLM mobile. All you have to do is visit KLM Mobile on your phone or mobile device and book a flight by August 13th to get a free lounge pass. At time of posting there were only 142 passes left to give away so your best bet is to book sooner than later to snag one of these passes. Full details can be found here