My school has a daily email newsletter which includes upcoming events and recent appearances of staff in the news. Today it informed us that this is National Depression Awareness Day. As someone who has dealt with depression, I thought I'd pass it along.
Take some time today to think about anyone in your life who suffers from this. Please realize that they can't just snap out of it and cheer up; most people don't really enjoy being miserable. Think about your reaction to them and whether you are patient or patronizing when dealing with them. See if there is some way you can help them to help themselves.
Here's Wellsphere's very thorough Depression link if you need more information.