Cononical has announced that they will be releasing Ubuntu for Android which enables to run Ubuntu within your Android based smartphones. In order to run Ubuntu within Android, it need to have a multi-core processor. Now a days most of the smartphones comes with dualcore or quadcore processor.
With desktop OS like ubuntu integrated in your smartphone it can be used for productivity and have desktop experience. It lets Android and Ubuntu share the same Linux kernel, so they can run at the same time â€“ Android for the phone experience and Ubuntu when docked. Though there is some delay in running Ubuntu and Android at a same time smartphone runs smoothly.You can also receive call, reply to messages, access phone files from the Ubuntu it self.
More information regarding ubuntu can be found on it official Ubuntu for Android page.