I use my trainer for drills. It helps break up the time(but not very fun).
Right now, a couple times a week, I am doing one legged drills- so ten minute warm up, then 3 sets of 5 minutes on each leg(so right leg,left leg, repeat 2 more times) Then I do a 10 minute cool down. With that, I have 50 minutes done. If I have more time I will add in a 10 minute hard effort inbetween the drills and the cool down.

That is just one idea of something to do on the trainer!