Hey! I'll join!
Aside from my other exercise (30-day shred, speed walking 6 days weekly), I have started 20-min fast running on the treadmill Monday to Friday. I started last week. I forgot how much I love running on the treadmill!
I did it Monday, and I did it again today. It was a bit harder today, but I still did it. At about 14:30 minutes I said to myself, "it's only, you only have to do 15 min if you want to today". Then the next time I looked it was 17 minutes and I thought, oh come on, 3 more minutes!! yay! helps that I have new inspiring music too!