To get a change in my routine, I like to draw these large posters, and try out different coloring and shading techniques. Using a variety of subjects, I get a feel for how appropriate a particular technique might be in a particular situation.
Additionally, this is exercise is a great way to gain perspective (no pun intended) on your art style; drawing an object out of context helps me think about how I render the qualities that go into that object, ultimately helping me grow as an artist (I hope).
If you’re interested in doing a similar project, I suggest getting any large surface on which you would enjoy drawing. Leave it someplace convenient and add to slowly.