A lot of the original PS3 are dying about now due to heat issues and poorly designed cooling, along with dust buildup etc. The infamous YLOD
The smaller chips in the later PS3 run much cooler
This.
I've had three (3) YLOD's on my launch model 60gig.
1st was in November '09, less than 12 hours before my birthday. I was playing Operation Flashpoint: Dragon Rising at the time. GF put her controller down to grab a snack, and I jacked up the sensitivity to max and spun around in circles while I was waiting. I didn't think about it at the time, but a game with a 32km draw distance, along with it spinning 360 degrees every quarter second, puts a huge stress on the system. After a few minutes, the system was toast! My fault, I know.
Pulled it apart, did the heat-gun fix, then played MW2 just fine for umpteen hours a day, for two months. Stopped playing game in January due to a new job, started playing again in Feb. Got my second YLOD in mid-Feb, while playing Soul Caliber 4.
Fixed that again, and let it sit for a few weeks. Picked it back up in March, played FF13, and 14 hours into the game over a weekend (all at once), I got another YLOD.
For those that don't know, the main YLOD issue is that the system gets so hot, it melts the solder on the board. This then causes errors that the system reads, and spits out a YLOD. Looking it up, the board has to be hitting at least 180C in order for this to be happening.
I had this huge plan to put everything in a custom enclosure, and put it all into a small fish tank with mineral oil and a small external rad/pump/etc. Still may do that for GT5, but right now I've found a temporary fix in the form of a nice sized fan constantly pointed at it.
Also, before anyone jumps down my throat, my PS3 has ALWAYS been taken care of, outside of seeing a stupid number of hours on or playing games. No dust, it's own wooden slat shelf in a room that doesn't get above 65F in the dead of Summer, etc. I was unemployed for about a year, with a large sum of money in the bank. This allowed me to..well..relax a little.
So yeah, it happens, but usually only to older models, especially launch model 60gigs.