This is the place to come if you want a forum signature fast. Use one of the tools to make an image then use the bbcode supplied to use it in any common forum software. Alternatively you can use the new signature wizard to design a banner for your facebook page, just choose the facebook size image, upload your art or choose from several categories and get designing!
The old signature wizard is still popular to this day.
Or why not try making a funny sign or have you ever wondered what your own grave could look like?
Or do you want to share your last.fm music with others?
Or how about forum a signature on which people can leave graffitti?