Deb asked me the other day if it was possible her sister's TV had become infected by a virus of some kind, since it's been playing up very badly. They usually have to unplug it at the wall to "reboot" it a couple of times to get it to turn on, and the remote works maybe 50% of the time. My first thought was no, although the TV undoubtedly has a general-purpose computer inside, there's no viable infection vector. There's also no tangible benefit to anyone to write such a virus, even if they could get it into the TV. In all likelihood, the TV is just broken somehow.
However, there's one crazy possibility. Keeping in mind that I don't know quite enough about the protocols and systems involved, with their Playstation 3 connected to the internet, if they play a video over the HDMI connection and that video has some malicious code inside it somehow (maybe a buffer overrun) then there's a slight chance that such a video signal might infect the computer in the TV with a virus. The only thing it could really do from there is break the TV, though, which doesn't really benefit anyone ... except competing TV manufacturers. After all, if you buy a Toshiba TV and it breaks six months later, are you going to buy another Toshiba? You'll probably look to another manufacturer, and those guys are the ones who would write a TV-bricking virus targeting their competitors, in the hopes that you will buy from them instead. It's not a foolproof plan, but it has a slight chance of success. Sometimes that's enough.
With new TVs connecting straight to the internet, we may need to patch our TV operating systems regularly from now on, along with everything else in the house.
Mokalus of Borg
PS - Although most manufacturers are unlikely to be that diligent in issuing patches.
PPS - And most devices won't be worthwhile targets for malware.