Times when lying seems okay:

When the truth sounds like a ridiculous excuse.

When someone is trying to kill you.

When you get caught in a previous lie and need to weave a sticky web.

When the person you are talking to is being unreasonable (i.e. see #2).

When people are pressuring you to do something

With regard to this last item on the list, an example would be a situation in which your family wants you to practice a particular religion -- the Hatian religion "VouDou," for example.  Or if that is a bad example, consider a situation in which your elders believe that the computer is the devil and that if you use it you are the devil.  In both examples, people are pressuring you about something.  In a perfect world, you would be able to tell them to knock it off, snap out of it.  However, in the real world it may cause you a lot of difficulty if you insist on telling unreasonable people the truth. Maybe you are willing to work with them and help them to be reasonable, but you should not be obligated to do so in every damn situation that turns unreasonable.