Almost all travel makes me hypomanic. It's a lot less fun when sleeping only a couple hours makes you tired instead of wired. My favorite, I think, was being hypomanic in Seattle, though it had more to do with the company I kept than the city I was in.

I travel a lot - flew about 43K miles in 2011 and spent over 100 days away from home, and there are several trips on the books for 2012 already. And I've actually cut back. I love to travel, but it's so hard on me in terms of mood swings.