The Narrows, Zion National Park - photo courtesy of pdphoto.org
The Narrows is a great hike - but can be a bit chilly in the spring and fall. It's best done in the summer. An even more incredible hike is Orderville Canyon. It's a 13 mile point to point that ENDS in the Narrows. It can be a bit technical and difficult to do without a rope. Be sure to check the weather for thunderstorms in the area and DON'T do it if they're forecasted!
The Narrows is one of the best hikes I've ever done. Be sure to do the orientation, know the flood danger level and be prepared but it is unmatched scenery and hiking in ankle deep to knee deep to swimming at times makes for an incredible day!