I have not retouched this picture except to clean up the colors due to a bad scan. For reference, I was 6'2" at the time this picture was taken. This is in the office of the professor who eventually kept the lamp. Obviously, I couldn't take this home on the bus...

My lava lamp was a big success. It ended up being a little cloudy, but it's still quite useable. I had to up the wattage from the standard 40W to 100W to cut the heat up time down to 12 minutes. It was a great hit with the kids when we did the presentations. BUT- here are a few things that I learned in the process of making it..
Make sure the dye doesn't have a solid portion. If there is one, it will settle out and make the clear liquid cloudy.
The base must be both solid and not likely to burst into flames under several hours of heat from the light.
When you cork the lamp, I suggest that you have it going for a few hours first, so you don't easily blow the top out after that. Either way, keep the lamp pointed in a safe (up) direction.

Problems with this one:
It's cloudy- I goofed on the dye I used to stain the blobs.
It stops working after ~7 hours- I suspect that putting a small iron spike through the center of the cork (and down into the liquid) would create a big enough heat sink that the temperature gradient wouldn't break down then.