How about a gun?
Remodeling my sister's house awhile back. She had a china cabinet type piece built in as part of a wall in the dinning room. She wanted it out and just a normal wall there so while ripping it apart we found a .357 S&W revolver. She freaked out for a minute, thinking it was a murder weapon or something bad till my Dad an I realized it was a very well made (so as to look very much like a real revolver) CO2 powered pellet pistol. That was fun.