Do you mean Citypass? http://www.citypass.com I'm guessing not, because there isn't one for Washington D.C.

I can't really speak for New York because it's now a while since our last trip there, but we did get the Citypass for Boston http://www.citypass.com/city/boston.html?id=rm3h4cZV but its certainly not as expensive as the price you quote (Citypass is $44 now, I think it was $38 when we went). This allows entry to:-

New England Aquarium
Museum of Fine Arts
Museum of Science
Skywalk Observatory
and one of
Harvard Museum of Natural History
JFK Library and Museum

We opted for the Harvard Natural History Museum which was excellent. We didn't manage to get to the Museum of Fine Arts, but did all the rest. The Aquarium and Museum of Science were excellent, although busy especially with school trips and the Skywalk in the Prudential Center is a must do for great views.
If your interests include the places mentioned then it will be worth it, but obviously if you don't think you are interested in 2 or more of the attractions you will probably be better off paying on the door.
One final point on the Citypass, as with all of the passes across the USA you can purchase from your first attraction, i.e. we went to the Aquarium first and purchased it there. Any further questions on the Citypass please let me now?

As for D.C. I am tempted to say don't bother with any paid for passes. A lot (probably 90%) of the major attractions in DC are free (all the Smithsonian Museums, Washington Monument, Capitol Building etc) so I would start with these places and go from there. Believe me, you will not stop in DC there is so much to get round and see. A couple of tips, firstly, with the the Washington Monument and Capitol Building tickets are free (as mentioned) but they are timed entry. Get down to the attraction you want to visit first thing, like 8am at the latest to guarantee tickets for that day. It was the period just after Christmas we went a few years back and it was very busy, so much so that despite early starts the Washington Monument tickets had all been snapped up (and we were getting there 8.15am onwards). Fortunately, the Capitol we were a bit luckier, and the timed entry was only an hour or so after we managed to get tickets. Definitely make the effort for both. Also, definitely make the Air and Space Museum a top top priority, it is absolutely brilliant and free!!!! There is an IMAX as well, which you will have to pay for but I think we managed to spend the best part of a day there, it really was excellent.
Other highlights, Arlington National Cemetery (hop on a train there), the theatre where Lincoln was shot (and the house opposite), the Spy Museum is supposed to be good but expensive (we didn't bother), Washington Zoo (Smithsonian, so free) and the visitors center for the White House (no tours available of the White House itself to the general public). Also, definitely at least take a peek at the FBI Building (no tours since 9/11), the Pentagon (it will be literally walk out, see and head back to the subway but there is the Pentagon Mall nearby, next stop up on the subway) and Georgetown is definitely worth spending some time (like a totally different city).

HTH, any further questions please fire away.

Ju