I came across this and thought it was interesting, if only because it is believed to be the only time a U.S. Supreme Court Justice said “Happy Halloween” from the bench.
During oral argument on October 31, 2005 in the case of Central Virginia Community College v. Katz, 126 S. Ct. 990 (2006), the following exchange took place (beginning at page 37 of the transcript) after a light bulb noisily went out:
JUSTICE O’CONNOR: A light bulb exploded.
CHIEF JUSTICE ROBERTS: It’s a trick they play on new Chief Justices all the time.
JUSTICE SCALIA: Happy Halloween.
CHIEF JUSTICE ROBERTS: [W]e’re even more in the dark now than before.
It is not clear from the transcript or the opinion whether any of the Justices or counsel appeared in costume.