I don't know about you, but I hate being unemployed. I like the security of a regular paycheck, being able to cover expenses (and maybe a few fun extras). I like contributing towards a goal, knowing that my skills and labor are useful to someone.
When you're unemployed, there may not be much you can do about the paycheck, but you don't have to feel useless. While you're job-hunting, you can also hunt for volunteer opportunities. Maybe there's a charity to which you used to donate money, before you lost your income—perhaps you can now donate your time. Or you might see fundraising events around town, and strike up a conversation with its members about their organization.
Think of your own areas of interest. Is there a cause that you feel passionate about? Do you know someone with heart disease? You could ask the American Heart Association if they can use you. Do you love animals? See if your local animal shelter needs help mucking out the kennels. Willing to pitch in anywhere? Try Volunteer Match to see if someone nearby can use your specialized skills.
I've become increasingly aware of the country's homeless population in recent years, particularly after the massive foreclosures and job losses in 2009. As a result, I offered to help out at one of our local homeless shelters. They can often use another pair of hands to help out with basic work like food preparation and cleaning up. The people I work with are great, and I'm much happier being useful.
You don't have to stop your job search; one or two afternoons a week leaves you plenty of time for job searching and interviews. And when you're done sending résumés into an unresponsive void, nothing helps to soothe the sting of rejection like showing up and helping out for a good cause.