The Native Development Kit for the BlackBerry PlayBook's BlackBerry Tablet OS hasn't been released to the public just yet (see our BlackBerry Developer Podcast for more details), but when it becomes available we should see a plethora of games become available. Developers can take any game developed for a POSIX environment and easily bring the code over to the QNX OS. From there it's just a matter of tweaking controls for the PlayBook's user interface and sizing graphics for the appropriate resolution.
In this video recorded at the Ask the Experts booth at BlackBerry World, we get an explanation of how easy it was to port Quake III over to QNX via the NDK and of course we get to see some multiplayer first person shoot em up action. Check it out!