One of the neatest short hikes (4 mile loop) around is at the top of Roanoke Mountain. It is suitable for almost anybody (except those in wheelchairs) and briefly gives a taste of the Blue Ridge experience with just enough uphill climbing to make the heart beat just a little faster.
The Roanoke Mountain loop hike is not something grizzled backpackers and avid dayhikers are going to flock to, but it's a wonderful place to go if you only have about an hour of down time and just want to kick up a little mountain dust. You can be there from downtown Roanoke in less than 15 minutes by following Walnut Street up Mill Mountain and then keep going until it hits the Blue Ridge Parkway. The loop road around the mountain begins just a tad to the left of that intersection.