On Instagram, this idea kind of snowballed among a few fellow artists the other night - "15secskull challenge". Pretty straight forward: try drawing a skull in 15 secs while recording yourself at the same time, hashtag #15secskull when you post. Feel free to try it out! Go go go! It's pretty rad seeing what folks come up with!
Here's what I came up with: http://instagram.com/p/a97ADWDM5p/