Requirements:

• Mobile phone which can record ring tones*
• A quiet moment alone in house

* - or you could do this with a microphone, recording device and computer if you are technically inclined

Method:

Use "quiet moment alone in house" to record your household telephone ring as your ring tone for your mobile phone. For bonus points, if your phone supports it, also record your doorbell ring or door knocker for your SMS (text) message alert.

Results:

Giggle in amusement each time your phone rings and someone in your household tries to answer the household phone to no result, or you receive a text message and they go to answer the front door.