Everyone has 30 minutes a day and a dvd player. What I recommend for anyone starting to work out is Jillian Michaels' 30 day Shred.
I agree, Jillian Michaels videos are the best. Its nice, for me personally, to have someone telling you what to do/how to do it. Makes it hard to cop out too, she knows, she always knows
Also, a few things that I incorporate into my daily workout routine-
-crunches + a medicine ball (makes 'em a little more interesting) https://www.youtube.com/watch?v=1Hf_5_rmaOc
-squats + a medicine ball (same, and it works more muscles that regular squats)
hold the medicine ball in front of you, do a squat, come back up, then extend your arms above you with the medicine ball, then bring it back to in front of you...thats 1 rep
-side planks (these are pretty hard...look up instructions online)
these are also difficult...instructions on this page, along with a few other exercises The Ultimate Medicine Ball Workout | Men's Health
A few other things to think about...
If you're bored, go for a walk, do a few exercises, have a dance party, anything active! Boredom eating is my absolute nemesis
Water is good, water is great. Repeat to self many times daily
When you ride..drop those stirrups for a while! Great for you position and a good workout!
Above all, always stay positive!