I started working on a browser-based, netlist-based SPICE interface. Why? I'm not sure, it seemed like a cool thing to do; I'm aware that there's some good web-based, schematic-based implementations already out there.
To start, I downloaded and compiled the original Spice3f5 from Berkeley. ( I think I'm going to make a tutorial about this later on, it took some work). Then I began creating a simple "Ajax"-based web-interface. You can take it for a spin here:
Here is an example that was saved via permalinking; anybody can do this to any circuit in order to share it or pass it around: