Fibber

From the back of the box:

FIBBER! is the family fun board game with a great new twist -- when players announce what number they've rolled, how can you find out if they're telling the truth when you can't see their die? By challenging, that's how -- Just say "Are you a Fibber?" Off comes the top of their dice shaker and if they were fibbing -- whoops -- back they go; but if they were telling the truth -- then back you go!