Rich Little's first impersonations, when he was a school boy in Ottawa, were of his teachers, which meant that his first fans were his classmates. And the effect probably wasn't a whole lot different from his concert Sunday night in Symphony Hall.

There's something intriguing and funny, and just a little mischievous maybe, about watching Rich Little imitate the great politicians and entertainers of our day. Especially when he puts the Little spin on them, taking their mannerisms and their personalities and making them just slightly more absurd."Welllll," says Little in the Ronald Reagan drawl, speaking at a press conference, "before I start speaking, I'd like to say something."

If it were just a matter of doing impressions of famous people, Little would be entertaining enough. Little's famous people, though, are full of one-liners.

"What would your advice be to someone in Utah who wanted to open a small business?" President Bush is asked at the same press conference.

"I'd open a large one and then wait," answers the president.

The comedian's political impressions were among his best. He's always done a great Richard Nixon, of course, partly because his deep-set eyes and the shape of his face lend themselves to the Nixon scowl-and-jowl. And his Ronald Reagan is also superb, as well as his Jimmy Carter.

His George Bush, as Little himself predicted in an interview a few weeks ago, is not perfect yet, largely because Bush is not exactly inimitable, and therefore not very imitable. Little did have the mannerisms down well, including the tilted head and the outstretched, pointing arm. But the voice seemed fairly generic.

These little imperfections didn't bother Sunday evening's crowd, who had spent $35 a ticket to see the master of mimicry in a benefit for The Children's Center for troubled children. The concert was sponsored by Gump and Ayers Real Estate.

Entertainers, particularly the classics like Jimmy Stewart and Johnny Carson, are also Little's speciality. His Carson is authentic down to the last grimace and twitch, and the voice is so real that you can close your eyes and imagine you're actually dozing off in front of the TV.

Little closed with a medley of short soliloquies from famous actors, most of them dead now, who had distinctive voices - from John Wayne to Jimmy Cagney. But these were straight pieces - actual re-creations of movie lines - and not as entertaining. Anyone under 20 in the audience probably found the finale a bit flat.

As Little's 11-year-old daughter once remarked, upon finally seeing Anthony Newley on TV (a singer her father often impersonates): "Dad, come here, somebody's doing your act. And you do it better."

Little might take a cue from his daughter and update his act to include a more current cast of characters. And the show would benefit from being a little more spontaneous. But these are just nitpicky complaints. If you ever get another chance to see Little in concert, don't miss it.