I've written before about multi-tasking (here, here, and here). In general, I think multi-tasking doesn't work and should be avoided. But does it hamper creativity?
In a study done by Teresa Amabile and others (see footnote), they found that having a fragmented day (ie, multi-tasking) didn't help bring out more ideas. Focusing on a single topic and collaborating with a single individual increased creativity.
I think about my typical day on site with a client. I have multiple meetings on different topics and don't seem to get a lot deep thinking work done. On Fridays, when I work from home and have more control over my day (and less meetings), I can carve out a large chunk of time to focus on a single topic and that's when I come up with some good solutions.
I've heard of organizations that are going to no email Fridays. I think the benefits will be the same. Without the distraction of email, they can focus on a single problem and let the creativity flow.
So pick a problem you've been trying to solve, block your calendar for half the day Friday, turn off the email, and get creative.
Teresa M. Amabile et al., “Time pressure and creativity in organizations: A longitudinal field study,” Harvard Business School working paper, Number 02-073, 2002