1,000 words to be precise. As Howard Bashman has very ably chronicled at How Appealing, the proposal to limit the word count in federal court appears to be progressing via a compromise that would reduce the word count from 14K to 13K. See Federal Appellate Briefs Might Have to Be Shorter.
On the oral advocacy side of the practice, see Taming the Butterflies Before a Supreme Court Argument, about lucky ties, special dinners, and other rituals before a big argument.
[And to read the arguments, click here and here.]
For even more excitement, how about a $58K sanctions award for filing a frivolous appeal (here)?