Urban Hiking is what I call the thing most of us do when we travel. We explore urban landscapes on foot, all day, days on end, til we simply can take no more. When I cannot travel, but feel the overwhelming need to wander, I go for an urban hike, in my home town. I am from Portland, so urban hiking is easy. I strap on my Chacos and backpack and hit the streets. I recommend seeking out neighborhoods unfamiliar yet interesting. Look up some tips on the web, or use twitter to find events or pub crawls downtown. I know what you're thinking, but trust me, it's really not lame. I've lived in Portland for 25 years and there are countless places I've never seen but should.
Act like you do when you're away: carry a map, ask strangers for directions. Bring your camera and take some photos. Walk into an unfamiliar cafe and grab a pastry. Eat street food. Be as unbiased as you can, and you will get a lot out of your adventure without ever leaving town.