One of the things I like best about Linux is the ability to do "everything" with commands and scripts. That reasonably makes me interested in having tasks done automatically with some (simple or not) scriptings, something "Home automation" if you want to call it that.

Let's forget all stuff like automating Linux administration, backing-up v.v... and think about the more informal and non-technical side to give some fun to the old computer and (if possible) to the house. For example, I think I can make my Debian box to announce the time with music and voice every hour, regardless you're in console mode or GUI. My next project will be having it silently check for my remote commands via Gmail and execute them etc...

So what is your idea of some automatic fun with Linux? Any ideas or suggestions are warmly welcome!

What about being able to monitor the temperature from various points around the house
& adjust the thermostat accordingly: http://www.dealextreme.com/details.dx/sku.7003
Or integrate with thermostate & web UI to be able to remotely correct the temp of your house?

Here are some of the things I'm working towards:

Alarm system integration: monitor to tell me if I left the garage door up & web ui to close it.

Phone system integration via asterisk.

As tablets become cheaper, a few discretely installed around the house could become video monitoring stations for cctv security system, intercom/video-intercom etc.

Lighting management: turn on/off outside lights at dusk

Sprinkler system management: Check the local forecast, or integrate with ground moisture levels to automate sprinklers
for most efficient use?