2-3 hours from Philly?
Well first off, there's all the stuff IN Philly--Art museum, the zoo, Liberty Bell, Independence Hall, Betsy Ross House, Franklin Institute, etc.
Then there's....
Clubbing on Delaware Avenue
Lancaster/PA dutch country
Gettysburg
New Hope, which is awesome in the fall/spring when it's still warm enough to sit at an outdoor bar and watch all the motorcycles, cool cars and weird people go by. There's also cool artsy-fartsy shops, overpriced secondhand stores and GREAT restaurants like Havana. Also a good cigar/pipe shop and a hot-sauce shop.
A football or hockey game may be in order, too.
South Street is worth wandering through.
Longwood Gardens and the other stuff in the Chadds Ford area is interesting, and it's a hit with the ladies.
King of Prussia Mall, one of the largest, although it's just another mall...you won't find much there you can't find in any other malls.
In NJ:
The NJ Aquarium in Camden is cool, and right across the river from PHL.
Princeton, which is kind of like New Hope only instead of hippies and goths it's Asians and yuppies, more overpriced shops and less outdoor bars.
You have to go to the beach!!! At that time of year, though, there won't be a whole lot to do--most of the resort towns start to turn into ghost towns, and most of the non-resort towns don't have much anyway, but it's definitely worth checking out. Some of the towns further north like Point Pleasant or Seaside my have more going on, but farther away.
There's ALWAYS action in Atlantic City, of course.
The Cape May zoo on Rt 9 is well worth visiting.
You could pick up an issue of
Weird New Jersey and go hunting for spooks, loonies, or wavers.
There is an excellent stationary wave at the Delaware Water Gap. Bring a surfboard or kayak and a wetsuit

Horse racing at Meadowlands? Dunno when the season ends, though.
You're like 3 hours from NYC, and you could easily get there by train if you don't want to drive. Of course, there's a boatload of stuff to do up there.
You're also not far Baltimore, MD where you can check out the inner harbor.
There's also some decent beaches in Delaware, and tax-free shopping.
Well, there's a couple suggestions
