As someone loving leds, I obviously couldn't nót think about making led cubes. A friend of mine built a 4x4x4 cube a while ago, which I helped programming. (We have this deal that if he needs something programmed, I will do it for him as long as he keeps supplying me with pizzas.) After that, since I already had the code, I built a small one too. (pic 1)
I wanted more than just the small single-colored cube, so I started building an RGB cube. (pic 2). Soldering the thing was terrible though. Each led has 4 pins, only spaced 0.6mm (0.02in) apart, so it was really hard not to accidentally solder some together. It did finish soldering it, but I haven't made the PCB's for it yet.
My friend took the other route, and started building an 8x8x8 cube. (see video). It took him ages to complete, (which makes sense, since there are 1024 leads that need to be soldered), but it was more than worth it. Luckily the same type of hardware could be used, but the old code I used for the small cubes wasn't fast enough for the big one, so I had to rewrite the entire code from scratch. This took quite a while, (and a lot of pizzas), but I'm very pleased with the way the code turned out. I do still have to program some extra modes.