The Rubin Museum looks interesting. I haven't been yet. The Neue Museum is another you may not have tried. The Frick? Here's a list you can review.

http://www.ny.com/museums/all.museums.html

You might check the calendar on nycvisit.com for the dates of your visit to see about anything special going on. Have you been up to Marjorie Eliot's salon on a Sunday for jazz? Have you been to the new Top of the Rock observatory? What about Dizzy's Coca Cola in the new Time Warner building. Have you had drinks in the Mandarin Oriental lobby bar?

You might be interested in the Not for Tourists guide
http://www.notfortourists.com/newyork.aspx

The Municipal Arts Society give some great tours and lectures.

Oh, and there's a backstage tour of the Metropolitan Opera House that's supposed to be great, too. And, you can sign up for some really fun eating tours/restaurants-with-an-expert evenings with the Institute for Culinary Education, not to mention one-time cooking courses -- New Yorkers love these. I swear almost everyone I know has tried one out at one time or the other.

Other Brooklyn ideas: Stroll down Atlantic Avenue between Bklyn Heights and Cobble Hill/Boerum Hill and visit the antique shops

oops, cut myself off. I was going to say the antique shops AND the burgeoning boutique scene. Smith Street south of Atlantic has tons of bistros, restaurants and boutiques. Grocery, the sleeper hit of Zagat's (last year/this year?) is located on Smith here. Court Street, which runs parallel to Smith also has lovely small-shop shopping and a fair share of vintage shops, especially further down south from Atlantic.

5th Avenue in Park Slope, Bklyn is another hot strip for both restaurants, shops and vintage shops (that's where Beacon's Closet is located).

Check out Brooklyn Academy of Music in up and coming Fort Greene for avant garde performances. The lovely opera house also houses BAM Rose Cinemas, known for interesting cinema choices. Fort Greene and Clinton Hill has a few choice restaurants, too, and some lovely architecture.

Actually all of the above are located in Brownstone Brooklyn, a beautiful "belt" of quintessentially lovely New York City neighborhoods.

I'd suggest getting a New York Magazine, so you know what's new, just oppening, just opened, opening soon and sales, lots of designer sales listed.

Also the Village Voice is another great source for anything New York.

Have a great time while you are here.

Just a side note.... if you're thinking of going to Beacon's Closet-- you might want to look into going to the one in Williamsburg (Brooklyn).. it is a bit out of the way -- it's much bigger than the 5th Ave. location (though 5th avenue is lovely for boutiquey shopping)

I took the Lincoln Center tour and it was awesome. My favorite part of the trip.

Ditto on the Lincoln Center tour - fascinating. We recently saw "Singing Astaire" at Birdland - a nice evening of great music.

Here is the link for the Rubin Museum mentioned above http://www.rmanyc.org it's on West 17th in part of the old Barney's department store. Looks very interesting and worth checking out!

Look at Craigslist in the Tv-Movies-Radio section, do a search for Extras, see if you can get on the set of a movie or TV show as an extra.

What a very cool idea!