This is one of those little pet peeves that I don't voice all that often for fear that the person I'm criticizing will come right back and point out a million grammatical errors that I have committed, but I found a site today that validated my belief, so I'm finally going to come out and say it: often is pronounced "offen." This is one of those things I really remember from 3rd grade, for some reason. The teacher made it very clear to us that the "t" was silent. I think my teacher was the only one to ever teach this, though, because everyone else IN THE ENTIRE ENGLISH SPEAKING WORLD says "off-ten."
Here you go.