Well, it is commonly called jailbreaking, Not exacty the kind of activity I like to spend time doing. I have been using, administering and programming on Unix machines for more than two decades now, and I get it as a personal offense if I am not given the root password of *my* machine. With the responsibilities that root passwords bring.
. The N900 has a CPU that is powerful enough to compile stuff, and lots of memory. I can connect to it via SSH and it will appear just like any other machine I use. But when the USB cable is detached, it is a fully-functional phone plus organizer plus media player plus ... ... ... Unbeatable.