I'd like to recommend you an online course which is available at Coursera , called Ignite your Creativity. It's already the 3rd week of the total 6, so I'm not sure you can join (yeah, I might recommend it a little late...), but as long as I know, there will be future sessions so you can add the course to your watchlist.
The course, for me, is really useful: I did not think that creativity can be discussed in so many ways. There are also assignments need to be done, so you are "forced" to use your creative thinking and come up with awesome ideas.
Furthermore, I recommend you search through the course catalogue, 'cause there are really good art-related courses (and other kind of courses as well! ). As you can see, I'm quite enthusiastic about MOOCs, I think this is an awesome opportunity to feed your brain and learn new things. One day you might need that knowledge, who knows