This is the coolest glitch ever! Just follow these steps:

You are going to need these in your house; a chair,table, and a lamp (anything that you can put onto the table).
Place the object and the chair somewhere in your house.
Make your sims sit on the chair.
Wait until they go to sleep.
While they are sleeping, go to the furniture icon and move the object on to the table.
Now get out of the furniture icon and you will see zzz's coming out of them.