I have three old Socket 7 computers in my closet, and one old laptop under my bed, so I have come up with ten things I can use them for. I still haven’t decided, but I really want to play some NES games.
Classic Video Game Console Emulation
Install as many old console emulators as you can find, get some ROMs, buy some Linux-compatible game controllers, connect the computer to your TV, and then play your favorite games from the past.
I know nothing about home automation, so here, have some links:
Home Automation 101 at Linux Home Automation
Linux and Home Automation
X10 Smart Home Automation with a Firecracker and Debian Linux
Home automation in GNU/Linux
Donate your computers computing power to a good cause such as finding aliens or curing cancer. Look through this list of distributed computing projects for Linux, and pick one that you think is important.
Install ZoneMinder and connect a few webcams to watch around your house. I was going to use a camera to check who’s there when somebody knocks on the door, but then I remembered I have a peephole.
Pimp Your Phone
Using Asterisk, you can do some awesome stuff such as music on hold and voice mail. To get started, I think Systm episode 5 looks useful, but it’s about 3 years old, so it might be a little outdated.
Install Gourmet Recipe Manager to manage your recipes, then maybe install some games so you have something to do while you’re waiting for the muffins to rise.
You can open Dungeons and Dragons maps in the GIMP, use a projector to project it onto a table, and then use a layer mask to hide unexplored parts of the map from the players.
Don’t want visitors messing up your computer? All you need for a guest computer is a browser like Lynx Firefox, so the guest can check their Facebook.
Watch Movies and TV Shows
Connect the computer to your TV, and watch movies and TV shows for free using websites such as veoh. Why pay for cable when you can watch the new episode of Lost a couple days later?
A lot of hobbies belong in the garage, and depending on what your hobby is, you will have different things on your garage computer. I would have pyrotechnic formulas, but you may have an Ohm’s law calculator or a bookmark to a motorcycle forum.