Well, If you need to make a phone call, twitter, facebook or whatever and have ubuntu/backtrack/debian/arch linux distribution running simultaneously, you can use "complete linux installer" to install linux distribution and then get another launcher like unity launcher to start up phone etc. while using linux. It works. Linux will not be mercilessly killed by android when you make or receive a call so you can return to where you were in linux. But I agree it is not as nice as a native installation of linux nor as cool as the user interface Canonical has designed.