Just been poking around on the main blackberry website and came across this offer.
When you arrive at the website you will see a series of BlackBerry product details scrolling through, the one you want is the last one (you can select it directly by clicking on the last little white circle toward the left hand side of the pages ) then click on each of the the little blue links to get the games themselves for FREE!
It seems that these games were initially given away to promote the launch of OS2.0 and although it says for a limited time only, they are still available!!
Can't see them myself in the normal app store.
For Modern Combat 2 you have to open this link directly from the browser on the playbook: