This list is not complete, I am updating it daily. Please make sure you check back for more places. If you know of something I haven't mentioned, I'd love your input, Leave a comment.
Strasburg Railroad. Take a scenic and educational (about 1 1/2 hours from Philadelphia) drive to get to the Strasburg Railway. While this is not in the immediate vicinity of the city, or South Jersey, you won't care when you see the look on your child's face as they board the amazing steam engine train. For $11 per adult (kids under 3 are free, 3-11-$6) you take a scenic 40 minute ride through the farms of Amish Country. Although it isn't necessary for a great day out, they also feature A Day out with Thomas various times throughout the year, and The Santa Express. If you live in the area and just visiting, this is a definite must see for your little train enthusiast (or toddler bordering on obsessive train behavior, like mine).
Longwood Gardens, Kennett Square, PA. This is great all year round. They have an amazing kids garden, holiday displays and events throughout the year. Kids under the age of 4 are free and a yearly pass is for a family of 5 is only $105. You can also get discounts for your guests when you bring them along. This is also a great place for the summer to let the kids walk around(without worrying about them getting out of your site) and get some fresh air. (They have an amazing children's garden) Every Monday from January 21st 2008 to May 19th 2008 you can participate in the gardens Kid's Story time. Enjoy a story and create a craft with the Garden's staff, for kids ages 3-5 from 10-10:30am and 10:45-11:15am.
The Pop Shop, Collingswood, NJ. If you're in the neighborhood or a hop over the bridge from Philadelphia, this is great place to eat with kids. The Pop Shop is a great family friendly restaurant with food for kids of all ages, they call it the American Diner meets California Cuisine. You can build your own burger or sit on an old fashioned stool and sip from a milk shake. They not only have 30 different varieties of grilled cheese, but an amazing selection of mouth watering fries to go with it. They have a great vegetarian menu, the best pancakes in South Jersey (as rated by south jersey magazine and my tummy) and the best kids menu in the nation (food geared towards kids with kid friendly portion sizes, gotta love it). It's great prices, family friendly atmosphere and love for kids definitely can't be beat.
Great tip: Saturdays mornings between 7:30 and 10:30, pajama wearing kids accompanied by a paying adult, eat breakfast for free (beverages not included).
International Sports Center, Cherry Hill, NJ. This indoor sports complex features a large Fun Zone featuring an interactive indoor jungle gym for children age 10 and under with a special area for toddlers. If you are looking for your kids to get into sports they have beginner, tot and advanced classes. This is also a great place for birthday parties. Click on this link for hours and admission to the fun zone. The hours for the fun zone during the week might interfere with dinner but the hours on the weekend are ideal!
Camden Riversharks, Campbell Field, Camden, New Jersey. I don't know why I didn't think of this sooner, or mention it and maybe it's because we really just took both kids there today so I didn't think of it. But for $44 (can't beat it) for the family of 4, (and that's for the "good" seats). We purchased the seats online and picked them up at the will call, they have great events and today happened to be public safety day so the place was filled with firetrucks and firemen, of course, my son thought it was the coolest thing. After taking in "red", we grabbed a bite to eat (you could probably pack snacks or eat before hand and just buy ice cream) and then found our seats. My kids lasted a whole 2 innings before they wanted to get up and my husband and I didn't think they would lost through the 4th inning, but after a carousel ride, playing in the Fun Zone (this does cost $5 but worth every penny) eating ice cream, cruising the stadium and a couple trips to the bathroom (yes, he stayed dry the entire time) before we knew it, it was the 9th inning and we took our seats for a great Fireworks Display (I believe they do it every Friday night). These fireworks beat out the ones we saw on the 4th of July by far. My son thought it was the greatest thing ever and my daughter, put her hand over her face and fell asleep (yes, she nodded off during the fireworks). A cool bonus, great scenery, and with the field being right next to the Ben Franklin Bridge, my train enthusiast caught glimpse of probably half a dozen train trips across the bridge. This is worth every penny. If you can't check it out this season, put it on your list for next. Oh yeah...if your child is small and doesn't need their own seat, no charge.
Morris Arboretum, Philadelphia, Pa. The Arboretum is an "interdisciplinary center that integrates art, science and the humanities. Thousands of rare and lovely woody plants, including some of Philadelphia's oldest, rarest, and largest trees, are set in a romantic, 92-acre, Victorian landscape garden of winding paths, streams, flowers and special garden areas". While you are there enjoy the Garden Railway, I know that would be a hit with my kids, and the out on a limb tree adventure. Check their website they have events going on all throughout the year guaranteed to entertain the entire family.
Camden Children's Garden, Camden, NJ. Located just across the street from the Adventure Aquarium the Camden's Children's Garden is designed to entertain and educate. Designed to explore the natural world and expose children and families to first hand horticultural experience for creative and imaginary play. The Gardens are only open Friday, Saturday and Sunday from 10am to 4pm.