Here's a webpage on strange local laws. [Link courtesy of Budd Schroeder]
I could make a few nominations.
18 US Code § 711a. “Woodsy Owl” character, name, or slogan
Whoever, except as authorized under rules and regulations issued by the Secretary, knowingly and for profit manufactures, reproduces, or uses the character “Woodsy Owl”, the name “Woodsy Owl”, or the associated slogan, “Give a Hoot, Don’t Pollute” shall be fined under this title or imprisoned not more than six months, or both.
And for those game businesses that make you buy tokens, there is
18 US Code § 336. Issuance of circulating obligations of less than $1
Whoever makes, issues, circulates, or pays out any note, check, memorandum, token, or other obligation for a less sum than $1, intended to circulate as money or to be received or used in lieu of lawful money of the United States, shall be fined under this title or imprisoned not more than six months, or both.
And just in case you wanted to give your pocket change as security on a loan (or perhaps use a coin collection for the same--
18 US Code § 337. Coins as security for loans
Whoever lends or borrows money or credit upon the security of such coins of the United States as the Secretary of the Treasury may from time to time designate by proclamation published in the Federal Register, during any period designated in such a proclamation, shall be fined under this title or imprisoned not more than one year, or both.
Hmm, and beware, you militaria collectors:
18 US Code § 704. Military medals or decorations
(a) In General.— Whoever knowingly wears, manufactures, or sells any decoration or medal authorized by Congress for the armed forces of the United States, or any of the service medals or badges awarded to the members of such forces, or the ribbon, button, or rosette of any such badge, decoration or medal, or any colorable imitation thereof, except when authorized under regulations made pursuant to law, shall be fined under this title or imprisoned not more than six months, or both.
And the Swiss get special protections not given other nation's symbols:
18 US Code § 708. Swiss Confederation coat of arms
Whoever, whether a corporation, partnership, unincorporated company, association, or person within the United States, willfully uses as a trade mark, commercial label, or portion thereof, or as an advertisement or insignia for any business or organization or for any trade or commercial purpose, the coat of arms of the Swiss Confederation, consisting of an upright white cross with equal arms and lines on a red ground, or any simulation thereof, shall be fined under this title or imprisoned not more than six months, or both.
And note that if you figure that Jane Fonda or someone else is a traitor, you have a LEGAL duty to tell the White House, or some federal judge about it:
18 US Code § 2382. Misprision of treason
Whoever, owing allegiance to the United States and having knowledge of the commission of any treason against them, conceals and does not, as soon as may be, disclose and make known the same to the President or to some judge of the United States, or to the governor or to some judge or justice of a particular State, is guilty of misprision of treason and shall be fined under this title or imprisoned not more than seven years, or both.
[Note--this dates from the days when the United States was a plural -- "against them," not "against it." Also note that a compliance with this law is liable to get you on various agency watch lists, at the very least the "crackpot watch lists."]