Figure drawing practice

I been trying to improve my drawing abilities, and one thing you often read is that the best way to do this is by drawing the human figure.  My wife thinks it's because enjoy looking at nubile naked women, but the fact of the matter is that drawing the figure forces you to improve like nothing else, because if it's a little off then the whole thing sucks.  It just so happens that most of the models who are willing to take their clothes off and have a picture taken are of the nubile persuasion.  If your tree doesn't look much like the tree you are trying to draw, it still looks passably like a tree and no one is the wiser.  I've signed up for an online series called "Life of Drawing" and so far have been pleased with my progress.