Michael and Chris Ferry used to think it was funny getting the Applebee's waiters and waitresses to do the birthday clap for his dad – even when it wasn't his birthday – when they grew up in New Jersey.

Now that they own their own businesses, they've got enough money to – as Spinal Tap once said – turn that prank up to 11. Instead of getting claps at restaurants, their dad, Chris Ferry, has gotten calls – more than 20,000 of them – for his 62nd birthday on Saturday because the two sons paid to plaster his number on a billboard on the Black Horse Pike in the Atlantic City area.

"WISH MY DAD HAPPY BIRTHDAY," the sign says, adding his cellphone number that, because of this, their dad doesn't use anymore. "Love, Your Sons." The sign, which will be there until April 6, cost $2,000 and the brothers split the expense. It certainly was a far cry from the Applebee's birthday wishes, which the two sons did not just for fun, but also to get free desserts.

"We really got him," said Michael Ferry, 28, who, along with his brother Chis, 30, now lives in the Boca Raton, Fla. area after growing up in Ventnor. Michael Ferry said his father is a pretty staight, down-the-middle conservative guy, so the two sons are having a little fun doing something to rankle him – even if he is taking it well.

"He's having fun with it because there is no other route he can take," Michael said.

Indeed, the father hasn't really seemed annoyed by it – yet – but the sons acknowledge that he has reason to feel that way.

They even took a video of their dad's phone just as many of the calls and texts wishing him a happy birthday were rolling through: The father, Chris Ferry, an insurance agent in Linwood, has had to get a new phone since he's beeen getting calls from all over the United States and as far away as Germany, Kenya and Australia.