Omniglot has a lot of cool things, but one of my favorites is it's page on the 12480 script. There are several different scrips all along this concept, and you can write anything with it that can be expressed with a numeric value. In this way the scripts survive so long as numbers survive.
My favorite is the color script. I've often thought of making a conlang involving colors. Perhaps for a sentient group of alien octopus. The colors correspond to symbols within several of the other scripts, as well as IPA sounds, roughly a consonant and a vowel for each color.
12480 is inspiring for me, and if nothing else you should at least scroll down to the bottom and look at the sample scrips. They are gorgeous.