I don't mean it in the traditional sense of doing all kinds of different things at once, but rather alternating between different types of creative projects. For example, I've come to find that I really enjoy making fanvids for movies and TV shows that I like. Whenever I get stuck with my writing, I stop and work on a fanvid, which lets my brain think it's having a break doing something fun while also keeping the creative portion of it chugging along. Plus, I have something immediately tangible to show for my efforts and since we tend to be reward-based creatures, this helps reinforce my motivation to keep going in all facets of my creative life.
Common writer advice is when you're stuck, to step away from the piece and do something else. I've found this works almost 99.9% of the time. Of course, sometimes you just have to push through the block, but generally it doesn't hurt to work on something else for a little bit to recharge the batteries.
What sort of things do you do outside of writing when you need a break? Do you think it helps to keep in that creative mindset or "zone"?