For Week 2, I'm instructed to walk for 5 minutes, then to spend 20 minutes in this cycle: 90 seconds running/2 minutes walking/repeat.
It went really well this evening! I had just a little "catch" in my side near the end, but it wasn't bad. Afterward I felt like I'd gotten a good workout without being miserable.
That's what I'm liking about this plan. It's great exercise, but I don't feel like I'm going to die at the end of the workout, so I'm actually looking forward to the next time. Much better than, say, trying to run a mile straight through when I've never been a runner. I've done that before, and it's really not fun.