This headline in the North Raleigh News makes a common error: throwing a second "i" into what should be "minuscule." The Web version of the story corrects the problem.
The word, meaning "tiny" or "very small," comes from French and Latin. It is tempting to write "mini" as the first four letters because of that definition. According to this site, some dictionaries are open to the "mini" spelling, and the dictionary on my computer recognizes the "mini" version as a non-standard spelling.
The AP Stylebook, however, prefers the traditional spelling. So do I.