If you find yourself in Anchorage with a couple of hours to spare, a drive down the Seward Highway to the Portage Glacier is a must do.
The Seward Highway itself is a simply gorgeous route, designated as a National Scenic Byway. In it's entiretly it runs the 125 miles in between Seward and Anchorage. If you have time for a full day trip, you can take it all the way to Seward. However, if you're more like me and end up with just a couple of hours to spare you can drive the first half from Anchorage down to the Portage Glacier and take in some great Alaskan views.