It doesn't matter if you do all the error checking in the world, or if you have the most beautiful graphics, if your site or application design isn't usable, it's not going to do well. Get input and advice on usability and user interface issues here.
Print Definition is a wild idea I got a while back. The idea was that var_dump() didn't cut it when it came to outputting complex data structures, so why not make a custom routine to output these things?
And then, I decided to put it to practical use: why not allow the user to change the configuration and see instantly how the changes affect the outcome?
What do you think of it? I think it's mad cool :3 (but I could be wrong)