Here's a few of my favorite projects, pulled from my old site.LEGO/K'Nex laptop
While hunting for something fun and original to do, I was inspired by a LEGO desktop, and decided to make a LEGO laptop. Unfortunately I couldn't find enough blocks to support the screen (and nowhere near enough to make a Turing-complete purely LEGO computer). Fortunately K'Nex worked nicely, and is comfortable to use. At the moment it has Red Hat Linux 7.1 (circa 2001), and I'm hunting for a newer OS which will run on it.
Sometime around 2000, my parents let me cut a hole between my wall and my brother's closet and call it a secret door. At first, it was pretty short (about half as tall as the picture). I left stuff in front of it so it wasn't immediately visible, and a peephole above it to see if someone was on the other side.
Several years ago, I decided to upgrade it. At the time, it was so short I could barely squeeze through it. I made it much taller so I could duck through it, and covered my side with the back of a cabinet. Next, I took the cabinet, ripped out it's shelves (so it was just a box with doors and an open back), and lined it up with the door. Finally, I covered my side with Starcraft 2 screenshots, to disguise the door.
Electric light switch
My first design used pulleys, but the strings had to turn a corner which added far too much friction. The second (and current) design uses a DPDT (double pole double throw) switch, which flips power and neutral to control the direction of a motor. The actual switcher is half of an internal hard drive's cover. I'm toying with the idea of using some sort of light sensor (possibly an optical mouse) to control my light switch with a laser.
Glow in the dark panel
Very simple, just a 2'x4' panel with a few coats of glow in the dark paint on it. A blue-violet laser (405nm) works wonderfully for writing on it, even though it fades quickly.
A couple years ago, I tried out LARPing (live action roleplaying). I noticed how much chainmail cost, and decided to see if I could make it. While it took way too much time to be worth selling, it's a lot of fun to make. I've made a few other pieces, but none are complete. This coif is made of steel wire. I've also used aluminum wire. Steel actually works as real armor, but gets pretty heavy even for small things. Aluminum is much lighter and can be repaired by hand, but can be pulled apart incredibly easily.