Massachusetts General Laws Part I. Administration of the Government (Ch. 1-182) Ch. 44, § 53I

A city or town, for the celebration of the two hundredth, two hundred and fiftieth, three hundredth and three hundred and fiftieth anniversary of its settlement or incorporation, and for the celebration of any semicentennial anniversary occurring thereafter, or for other special celebrations or events sponsored by the city or town for the benefit, enjoyment and edification of its residents and visitors, may appropriate money annually during the 5 years preceding such anniversary or special event. Notwithstanding the provisions of section 53 or any other general or special law to the contrary, such city or town may establish in its treasury a special fund in which shall be deposited such sums as may be appropriated by it under this section, and any and all sums received from the sale of commemorative items, admission charges or other monies received in connection with the anniversary or special event. Any and all such sums received by the treasurer shall be kept separate from other moneys, funds or property of such city or town and the principal and interest thereof may, from time to time upon the authorization of the mayor or city manager, as the case may be, the board of selectmen or the majority of any special committee established to plan such celebration or special event, be expended for the purposes of said celebration or special event in the year of such celebration or special event and in the year preceding or succeeding the same. Any surplus remaining in said special fund after such celebration or special event is concluded, shall be transferred by such treasurer into the treasury of such city or town.