Where’s the (roast) beef? It’s at Arby’s, and Facebook users who like the fast-food chain’s page can travel back in time and enjoy a Classic Roast Beef sandwich for just $0.64.

Arby’s is running the promotion to commemorate its 48th anniversary, using Facebook’s offers feature to make coupons available that its Facebook fans can redeem Monday for a Classic Roast Beef sandwich at the $0.64 price, representing 1964.

The Arby’s promotion takes advantage of Facebook’s timeline for pages, as users must scroll back to 1964 on the Arby’s timeline in order to access the coupon.

Readers: Would you like to see more businesses make similar offers via Facebook?