Short bio: Computer Scientist, FOSS supporter (read more)
Tux Machines (TM)-specific
Sometimes, doing what you're told or permitted to do isn't enough. For decades, the geeks of the world have looked at common conventional items of consumer electronics, and wondered "could I do something else with this?" As Free operating systems such as GNU/Linux or NetBSD (which is famously quoted as running on anything, up to and including a toaster) increased in popularity, so did the number of people hacking away at getting their favourite OS running on strange devices for no reason other than the technical challenge. Pretty much everything these days from ADSL routers to Apple iPods is capable of running Linux. I even have a CD lying around somewhere with a bootable Debian GNU/Linux for Sega Dreamcast. It doesn't do much other than run Doom slowly, but it's pretty cool that it exists at all.
It's not often that an actual company encourages this kind of thing, but on rare occasions, it happens. One example would be copy-protection-happy homebrew-hating Sony. Since 2002, they have made and sold a "Linux Kit" for their PlayStation 2 console, which enables you to run the OS on the (admittedly rather feeble) PS2 hardware. And, more recently, the PLAYSTATION 3 has come supplied with everything you need, out of the box - such as an integrated hard disk, and the ability to run a monitor as a sensible resolution. As a result, a number of Linux distributions have been working on making the PLAYSTATION 3 a first-class system, as easy to use and install as a "regular" PC-based version.