Since I bought my first house I, like most home-owners, have decorating and adorned their property with many personal nick-nacks and features. Being a limited budget, I've made most of the things myself.

A map of London, made from two A-Zs! Basically, tear out every page, and sitck them together to make one large map.

The only trick is to build it horizontally, and stop after 2 or 3 lines. This will let you adjust the pieces so that the roads match up. (Hint: they won't always match, because the maps are adjusted to fit nicely on the page.)

Star Wars light switch - The second version of this paper overlay.

Simply print a design onto paper, fold along the centre line and cut two slots in it for the switches. Because you cut when folded, it's easy than trying to pierce a hole in the paper, and cut a rectangle out 'from the inside'.

This began life as a translucent DVD case. By mounting a switch on top, and a bulb inside, you have a basic night light. What's neat about this particular approach is that when you put a book on it (image: right) it presses down on the switch, turning off the light automatically!
Another clock - this one is made from playing cards, and mounted to the trap door to the loft.
By spraying (half of) a Twiglets tub you have a perfectly servicable pen holder! Naturally, I have two of these - the other being made from the other half.
By attaching a few pieces of LEGO to the side of the bedside table you can make a tablet holder. This particular tablet is used to control the lights, music, and other peripherals in my house.

Also See these pieces

An animating picture - hanging in my hall
A chess set, from the conservatory
A clock made from a CD - in many rooms
On my bedside table
Attached to the side of my bedside table