Lest we neglect New Jersey, the Garden State has many options for day trips and weekend getaways, often at a significant discount from more popular destinations on Long Island or in the Hudson Valley.
Here are some initial links:
All Getaways has a pretty standard list of Jersey destinations.
Google Books has a link to a tome on the subject.
AOL CityGuide has a list.
Yahoo’s list is bare bones but worth a look.
The New York Times says you can even snowboard in Jersey. Who knew?