A Cell Phone Game for Children

I was playing hide and seek with my 2 and 3 year olds, and came up with this variation.

Requirements

2 Cell phones, one of which with a speaker phone mode.

Instructions

1) Call the phone with the speaker phone mode, answer and put it in speaker mode.
2)Have someone hide the phone in another room.
3)Let the child try and find it by yelling into his phone.