Colorful costumes, clear-cut heroes, giggly girlfriends – and pirates. What could be more fun than Gilbert & Sullivan?

How about a little plot synopsis, for free?

That’s what the New York Gilbert & Sullivan Players are offering with their “Family Overture” series.

About an hour before the 3 p.m. matinees of “The Pirates of Penzance” (today), “The Mikado” (Jan. 18) and “The Gondoliers” (Jan. 25), troupe director Albert Bergeret and his musicians and singers will explain it all to you.

“‘Pirates’ particularly appeals to children because it’s about a bunch of grown-ups pretending to be pirates,” Bergeret says.

Not only that, he adds, but the patter songs – fast-talking people saying funny things – are appealing to all.

Today’s introduction to “Pirates” is at 1:45 p.m. at the City Center Theater, 145 W. 55th Street, between Sixth and Seventh avenues. Show your ticket and you’re in.

For information and tickets – $35 to $65 – visit the box office or call City Tix, (212) 581-1212. There’s a full schedule of shows at http://www.nygasp.org.