All you have to do is follow @BlackBerry on Twitter and answer RIM's questions on Twitter. If you are the 10th correct android you win.
In case you are wondering what gifts are up for grabs:
- 3 BlackBerry Bold 9900s
- 3 BlackBerry Bold 9900/9930 cases
- 15 case of RIM choice codes
- 3 BlackBerry Torch 9850s
- 20 BBMing Gloves
- 4 BlackBerry PlayBooks
- 5 BlackBerry Beanies
source - BlackBerry