I've been using a recumbent exercise bike for four months. I'm not bored with it because I change things up constantly. I'm not working at the same speed and intensity for more than 90 seconds at a time, ever.
Focus intently on your workout. Be totally in tune with your body. Be aware of when it's hard, and also notice when things are getting easier because you're in better shape. Focus on what muscles are getting sore as you work and enjoy that soreness, because that's progress!
I avoid boredom simply by focusing on what my body is doing, how it's feeling, and thinking about what I can do to make it a little more challenging next time.
A good music playlist helps too.
