Hide/Show Sidebar

Hi I’m using since today wordpress for my website (still local) and it works great so far.. 🙂
But today I searched hours for a plugin or hack that does allow to hide the right sidebar of the theme twentytwelve with something like a button in the header. So the user should be able to hide/show the sidebar.

I thought of a link Hide-Sidebar in the header and by clicking all it needs to do:
css( .site_content { width: 100% }

Thanks for your help.