Go buy a 6' length of foam pipe insulation - you know, the gray stuff with the slit.
Roll up a ball of tin foil, just small enough that it fits snugly into the end of the foam.
Wait for your wife to be fixing dinner in the kitchen.
Sneak into the room next to the kitchen, bend the foam around the wall and blow forcefully into the other end.
Listen for the POP!, soon to be followed by a yell of some sort.
She'll love you for it...trust me!
BTW...it works just as well with teenage daughters while they're chatting on the computer.