I doodled my friends on my flights to and from LA (to see Depeche Mode). The likenesses aren't that great, but I did them pretty quickly, the first and third ones in about half an hour each. This is the first time I've ever tried drawing portraits from life!
SFO->LAX:

The next one is a mini-doodle that I started in the hotel and finished up on the plane ride home (with no reference!):

LAX->SFO:

I like drawing hair. Facial proportions are still hard, but that's why I need more practice.