Due to a glitch in some of the graphics chips (GPUs) made by Nvidia, Apple is offering free of charge repair of affected MacBook Pro machines.
In July 2008, NVIDIA publicly acknowledged a higher than normal failure rate for some of their graphics processors due to a packaging defect. At that same time, NVIDIA assured Apple that Mac computers with these graphics processors were not affected. However, after an Apple-led investigation, Apple has determined that some MacBook Pro computers with the NVIDIA GeForce 8600M GT graphics processor may be affected. If the NVIDIA graphics processor in your MacBook Pro has failed, or fails within two years of the original date of purchase, a repair will be done free of charge, even if your MacBook Pro is out of warranty.
The issue was found on 15″ and 17″ MacBook Pros with NVIDIA GeForce 8600M video card. If you notice any distorted or scrambled video then you should contact Apple Support (no Saudi Arabia there, sorry).
You can read more about it at Apple’s support page.