How about.........

What if I word the 'birthday' joke a wee bit different? Told it to a few comics on the weekend, and noone got it...so obviously it either needs re-wording, or it just ain't funny! How about.....

Birthdays for boys don't change much from year to year. Whether they are one or twenty one...whether they get a Tonka Truck or a lap dance...all they really want to do is play with the box.

Funnier?
Better?
....or just scrap the joke all together?