From Christine Luff - About.com

Runners are often creatures of habit -- we run the same routes, at the same pace, usually during the same time of day. Here are some ways you can avoid getting stuck in a running rut, and make your runs more fun, interesting, and motivating.

Play Beat the Clock
I love doing this when I'm running an out-and-back route. Begin timing your run as soon as you start. At your turnaround point, hit the split button on your running watch/timer, or just take note of your time. Try increasing your pace on the way back, with the goal of beating your time for the first half.

Do a Random Interval Workout
Pick a landmark in the distance, such as a tree or a stop sign, and pick up the pace until you get to it. After you recover for a minute or two, choose another landmark and speed up again.

Do Some Hill Repeats
Plan a route that has at least one hill in it and, when you come to it, run up and down it a few times before moving on.

Get a Running Buddy
Do you usually run alone? Try to convince a friend or family member to come along with you -- even if it's just once a week. Even if they're slower than you, you'll find that helping someone else will help get you excited about running again. If you can't find anyone who will run with you, follow these tips to find a running group.

Count 'Em Up
If you run where there are a lot of other runners, try this game: Pick out a specific article of clothing, such as black running shorts, to look for during your run. Then count how many runners you see wearing that piece of clothing. If you're running with a friend, you can each guess how many you'll spot during the run and then see who comes the closest.

Be a Friendly Runner
If you normally keep to yourself during your runs, try to be more of an extrovert. You'll be amazed at how some people react to a simple hello or a big smile from a passing runner. The positive vibes you generate will help keep you motivated for the rest of your run.