not possible unless you have a custom OS loaded on to your playbook, each app market/store has programs written in different programming languages that their platform be it android, OS, Symbian, BB can understand so unless you can get a hold of android app source code and compile it into something a BB playbook can understand your pretty much out of luck
android-Java, C++, c#(if the developers good)
Apple - Objective C
BB-?? most developers skip the BB platform because the companies always near the verge of bankruptcy and almost 97% of users have android or Apple devices so BB market would be severely less profitable, also BB has such a pain-in-the-ass security system most developers dont want the million extra steps to get past it
Windows-c++, Java mostly