Wow small world. xD
I just did them for my drawing class as well yesterday. My professor timed us on it and gave us items. And we'd do a new drawing every half-hour. We had to draw the item and the class room (including people) without looking or lifting a pencil. We could do a quick glance after we drew for about a minute.
It was a lot of fun and she said I did an amazing job and that I improved so much by the end of the class (which is 3 hours, so 3 hours non-stop doing that.)