From now until Dec. 31, when customers buy two BlackBerry Playbook tablets, RIM will give a third Playbook for free. The deal, which applies to the 16 GB, 32 GB and 64 GB Playbook models, is all part of Blackberry's Back to business sale directed at, you guessed it, small businesses.

RIM is also giving anyone who buys a BlackBerry Playbook before the end of the year a free accessory. Customers can choose between the BlackBerry Leather Sleeve, a BlackBerry Charging Pad, or a six-foot high-speed HDMI cable.

RIM has a listing of all of the places where consumers can go buy BlackBerry Playbooks in sets of threes on its Web site.

Critics lambasted the BlackBerry Playbook for its difficult physical controls, poor memory management, middle-of-the-road battery life, and its lack of 3G. Furthermore, the tablet blocks any apps that rely on Google Maps or text-to-speech, yet its 16 GB model costs just as much as an Apple iPad 2 at $499.

Retailers have done their best to hack away at the hefty price, with some companies chopping off as much as $200, yet Playbook sales continue to stagnate. RIM hopes to attract more users to the BlackBerry Playbook with this sale, and also when it launches version 2.0 of the tablet's QNX-built operating system in February 2012.