Poor Jessica!

I hear ya -- there have been times that's all I was allowed to do too (and I'm an elliptical junkie, so

) But you still can get a good workout on the recumbent bike ... two suggestions to help with the boredom factor.
The first is music! Load up your iPod with great cardio songs and make it as fun as possible. Also, some people swear by audio books as a music alternative.
Second, try some HIIT (high intensity interval training). You'll get a better workout and the time seems to go by faster because you're changing what you're doing every two minutes or so. I saw one HIIT plan for a bike that was sprinting as fast as you can for ten seconds, recovering for 20 seconds, sprinting again for ten, recovering for 20 etc etc. Or you could do more traditional intervals of 60 seconds sprinting and two to four minutes recovering. Anything is better than just mindlessly chugging along at the same speed for the whole workout!
Good luck and hopefully you'll be cleared for more kinds of exercise soon.