Joe let me know about a thread on CrackBerryAddicted forums where SSJason found a way to port MeBoy to the BlackBerry OS. MeBoy is an emulator for J2ME and seems to work (with varying levels of success) on the BlackBerry OS. Way back in 2007 a couple of people got vNES to work for classic Nintendo games and we get quite a few questions about it every week so this is a dream come true for some.
The games are in no way optimized to work on a BlackBerry and may provide you with some atrocious gameplay framerates but it is fun just for the novelty. Just imagine getting Mario Brothers or Mike Tyson Punchout on your BlackBerry.
The instructions may not work so well for newbies but you can definitely try out the prebuilt installer that has Pokémon diamond, Mario and Yoshi, bomberman, final fantasy 3, and Zelda built into it. You will probably need to copy it to your SD card for manual installation.
Keep in mind that we did not find this so any questions should be directed to the forums at the link below. We take no responsibility if this screws up your BlackBerry but reports are pretty positive so far.