Twenty-five

Is the number of years in a silver wedding anniversary.  It is also the minimum cut-off age for election to the House of Representatives, the atomic number for manganese, the minimum age to rent a car without a co-signor, the number of cents in a quarter, the customary TCP port for SMTP (the incoming email protocol), a freeway going between New Mexico and Wyoming, the size of a full major league baseball team roster, the number of points required to win a set in volleyball (under rally scoring rules), and a square number (which often appears in demonstrations of Pythagorean's theorem).

I'm glad that it is such an important number.