What any good card carrying member of the Church of Jesus Christ of Latter-Day Saints should have on their person. A Temple Recommend is necesarry to be able to get into a Mormon Temple, unless it hasn't been dedicated yet. To get this little paper card you need to have an interview with your Bishop, and then the Stake President. Both interviews are pretty simple and revolve around whether or not you are worthy to enter the temple. The main questions asked are something like:

Do you believe that Jesus Christ is you saviour?
Do you believe that Joseph Smith restored the true Gospel to this Earth?
Do you believe that (current prophet) is the prophet, seer and revelator?
Have you paid a full tithe?
And most importantly,
Do you believe that you are worthy to enter the Temple?

My experience has been that this isn't a really in depth grilling. You're made aware of the qualifications, and basically make the decision yourself.

One question that I'm sure bothers some people is the one about tithing. Tithing is defined by the Church as giving 10% of your income. If you don't do this, you cannot get a recommend. So, you can say you have to pay to get into the Temple for fun. You also have to try follow all the other commandments to the best of your ability.

A temple recommend is good for about two years, or shorter. The Church actively encourages every member to obtain one, even if they can't get to a temple. It's a good reason to talk to the Bishop, and evaluate how you're doing in the Church.