DJ Steve Boy does free podcasts every month or so of high-energy hour-long songs. He has interval and constant ones arranged by BPM. His website is http://djsteveboy.com/ - list of available music is available under the archives.
On the days I don't feel like working out, I make myself change into my comfy workout clothes and put on my tennis shoes. I find that, after I am dressed and ready to go, I am 90% more likely to workout than if I had stayed in my jeans or dress clothes. Now, I automatically change when I get home!
I'm lucky enough to work where there is a large family restroom. EVERY time I visit (no excuses!), I set a timer to 2 minutes and do some intense cardio. This is enough to get my heart rate up and boost my metabolism throughout the day. Since I drink so much water, I burn about 150 calories/day!
Everyone is short on time and long commutes do not help with this! To fit in some strength training on the freeway, I have created a series of arm movements (one at a time, of course) that I can do while driving. These involve pulsing pushing arm circles etc. Just put on some music and experiment!