Elliptical Workout Ideas?

[Alcyon]

I'm looking to change up my cardio workout...  Due to multiple knee and ankle injuries, running is out of the question.  I like biking/spinning, but the bikes at my gym don't work for me (they make my knees pop - weird).  

This is my current workout:

Nautilus Stairmaster - 10 minutes
1 min - 65 steps/min
1 min - 70 steps/min

1 min - 75 steps/min

1 min - 80 steps/min
1 min - 85 steps/min
Reverse for the last 5 minutes

Precor Elliptical - 20 minutes
Starting with an incline of 10 and a resistance of 5 for 1 min and increasing both incline and resistance every minute while reversing directions every other minute for 10 minutes (at 10 mintues the incline is at 19 and the resistance at 14).  Then the reverse for the remaining 10 minutes.  

What have you all got for me?  

[Bacos]

I use the workouts on the machines. On the ARC, I vary between hills/strength/shaping, on the elliptical I do the video trails, rolling hills, random, cardio... And then set to a challenging average resistance.