I have played this offline, and it's lots of fun.

Setup and moves as in standard backgammon.
Opening roll as in standard backgammon, the one who wins the opening roll moves the given dice.

On every roll after the opening roll:
When the dice are rolled, only the player on roll (from now on I'll call him "Player A") gets to see what he rolled. Before Player A makes his move he must tell his opponent ("Player B") what he rolled, or he can bluff and say he rolled something else.
Now Player B can either accept or reject Player A's claim.

-If Player B accepts, Player A makes his move using the dice he claimed to have rolled. Player B will never know if it was a bluff or not.

-If Player B rejects, and Player A was bluffing, Player B gets to choose what dice Player A should use.

-If Player B rejects, but Player A was not bluffing, Player A can choose what dice to use.


This is the only difference from standard backgammon, so it might be easy to implement.
It also works well in cube matches.