What do we call a 250th Anniversary?

According to Wikipedia, the preferred term for a 250th anniversary is Sestercentennial.  The number 2½ is expressed in Latin as "half-three". The term relates to being halfway from the second integer to the third integer. In Latin this is "Sestertius" which is a contraction of semis (halfway) tertius (third) - hence Sestercentennial.

Other terms that have been used include:

• Semiquincentennial - Probably a modern coined term: semi- (half) × quin (5) × cen(t)- (100) × centennial (250 years).
• Bicenquinquagenary - Used by Princeton University in 1996 and Washington and Lee University in 1999. It is a coined word for an anniversary of 250 years, but the elements of the word literally refer to an anniversary of 10,000 years, as follows: bi- (2) × cen(t)- (100) × quinquagenary (50 years).
• Quarter-millennial - Meaning one fourth of one thousand years.

Source:  http://en.wikipedia.org/wiki/Anniversary

What other towns and cities in Massachusetts are turning 250 in 2011?