1. Music. If you don't have an MP3 player, you should go out and buy one. Load your favorite music onto it and let it give you energy to workout. Music will help the workout go by faster (if it's music you enjoy) and help motivate you if the beat is fast enough.
2. Add New Exercises. One of the biggest reasons that an exercise routine can get boring is that you're doing the same thing every single day week after week, month after month. To avoid this repetitiveness, change your routine every few weeks. Once you get bored with regular squats, try some front squats or overhead squats. If you get bored bench pressing with dumbbells, try barbells. Instead of running, go swimming or biking. Adding new exercises can also make your routine more effective. When you do the same exercises over and over again, your muscle begins to memorize the exercise and it becomes less effective.
3. Crossfit. If you're looking to radically change your exercise routine and try something new, look into Crossfit. Crossfit is a fast paced, very high intensity workout that will force you to get in shape real quick. It does require some equipment so a gym is necessary but everything else you need is on their website. Everyday they'll post a new workout and though they may look easy, they're extremely challenging. The workouts are quick but intense which saves you time since they combine both cardiovascular and strength training elements into one workout.
4. Go Outside. Working out doesn't have to happen in a gym. If you get bored running on a treadmill or bench pressing, go outside and have some fun. Pick any sport you like to play and it'll probably be a good workout. Instead of using a treadmill, find a path to run.
5. Workout Buddy. Finding a workout buddy is good for a lot of reasons but mainly, it can help make exercising more enjoyable. Assuming your workout buddy is somewhat cool to talk to, you'll have someone to hang out with for about an hour every time you exercise.