Getting motivated and getting things done

It's a bright, sunny Sunday morning, and you have all day ahead of you free to work on that huge assignment that is due way sooner than you would like it to be. As you lie in bed contemplating your toenails, and checking all the overnight happenings on social media, you think to yourself 'All I need is a bit of motivation so I can get out of bed and get started'. Ah, motivation! That mythical magic bullet, that elusive beast you imbue with the power to solve all life's problems - our best friend, and worst enemy. But how do you get... and stay... motivated?