Hi.
Some of you may notice that in my signature I have a cool brawl card for which you can level up. It's a free thing, and they do MarioKart Wii licenses as well.
To find out more and to make one yourself, go to:
smartSIG
...and go from there! Pick your favourite characters, your favourite stage and put in your friend code (optional) and there you go! A BBCode will appear. Put this into your signature (get rid of the speech marks in the link codes for it to work properly) and voila! You're set!