I did 6 x 0.5mi @ 3:00 (6:00 pace) with 400 recovery. It was a tough workout. On each repeat, the first quarter felt easy and "slow", but the second quarter felt like work. I definitely need to do more long intervals to get my body used to that pace for longer runs.
Warmup: 0.65 mi easy with a couple of strides in the middle.
Cooldown: 0.35 mi easy.
Evidentally, I didn't stop my watch at the end of the workout. I looked at the distance and time though. Plus you can see from the pace graph where things got crazy (like when I got in my car and drove off).