new to PS and wanted to know where the 'town center' is

There are two "main drags": 5th Avenue and 7th Avenue, from Flatbush Avenue to maybe 15th Street.

What kind of family hangouts are you looking for, and what kind of community are you coming from? If you are looking for McDonalds, Burger King, and other national fast-food chains, there are some here, but not many.

We instead have numerous small restaurants, offering a wide variety of cuisines (including "American"), which generally serve much better food (at somewhat higher prices) than an Applebees or an Olive Garden.

If you can be more specific about the reasons for your disappointment, there are many here who can be helpful.

I would argue the neighborhood has a few centers, but one of them is Union St, between 7th and 5th Ave.

When you visited, where were you, specifically? If you were looking at apartments, you should know that realtors are famous for "stretching" neighborhood boundaries, so its possible that you weren't in Park Slope proper.
Agree with other posters above that "town center" (a funny concept in the city, really) would usually be defined as 7th and 5th ave, mostly from Flatbush ave to the north, and 15th street to the south. Within these boundaries, the further north you are, the more street life and family stuff you will find. It is important to recognize that this is largely a residential neighborhood, and businesses may be smaller, and there will be relatively few chain stores.
If you were in this area, and you are still asking this question, then PS might not be the right location for you.

In most of America, chains are where people eat. I asked OP where she is coming from, and what kind of family hangouts she might be looking for.

I know that anyone moving here from my home town of Rochester, NY, or from most suburban areas, would wonder why they're not seeing Red Lobster and Chili's and so on and so forth.

In other words, no hostility at all. And snark is not what is needed here.

Aubrey, if you've got small children, some local playgrounds are:

-3rd Street (just inside the main entrance to Prospect Park, and follow the immediate path on your right)

-9th Street (past the arches on Prospect Park West and follow the path on your right). This one is bigger/better for older kids

-5th Avenue between 3rd and 4th Streets.

Also, Prospect Park is a great place to hang out and have picnics. Lots of open grassy areas, and paved paths for biking with the kids.

Also inside Prospect Park is a zoo, a carousel, and an Audubon center that runs a beautiful electric boat ride on Thursdays through Sundays on Prospect Park Lake. www.prospectpark.org

Lots of kids here play AYSO soccer at the Parade Grounds on weekends. That's a great way to meet other families, if your kids are interested. www.brooklynayso.org

Lots of restaurants here are kid-friendly. Though I despise it and hate the food, Two Boots on 2nd St. between 7th and 8th Avenues is quite popular. Kids can walk up the couple of steps to peer into the open kitchen, and the cooks will hand them bits of pizza dough to play with. Pizza/pasta/kids' menu, with grown-up food too.

On Saturdays, the Grand Army Plaza greenmarket is overflowing with vendors and shoppers. They have flowers, vegetables, fruits, eggs, fish, meat, you name it.

There is a children's museum nearby, in Crown Heights. Best for 5 and under. www.brooklynkids.org

The Brooklyn Botanic Garden is within walking distance, and just beautiful. There's a children's garden within. Closed Mondays. www.bbg.org

Enjoy.

The closest thing to a traditional "Main Drag" would probably be the Atlantic Terminal/Atlantic Center complex on Flatbush and Atlantic (Which is technically not in Park Slope, but across the street from it). It is a mall with parking, a target, Applebees, supermarket, and big box stores like Marshalls, Old Navy, etc...Having said that though, it is really not what the most of the borough is like...If that is the sort of thing you are looking for, you might be happier in the suburbs...

Also, where were you looking? Real estate brokers, Craigslist, etc. have stretched "Park Slope" to be far beyond the common local definitions, so you may not have even been in the "real" Park Slope...

from flatbush to the prospect express way. from 4th ave to the park is the borders.

no real town centers, just um 5th ave and 7th ave as the main shopping strips. with union and 9th st dotted in between.

Note: no response from OP... she's long gone!

could be a trolling.

The Moderator team examined this person's background and presence elsewhere on the web and determined it not to be just another troll, best as we could tell.

The OP's own accounts elsewhere on the web correspond to what she has mentioned here.

Jeffrey.. So it sounds like a person who just "happened" on to this forum tooling around the net looking for information and posted a question and disappeared.Happens all the time.

jeffrey wrote: The Moderator team examined this person's background and presence elsewhere on the web and determined it not to be just another troll, best as we could tell.

The OP's own accounts elsewhere on the web correspond to what she has mentioned here.

A little big brotherish, no?

Hee. If folks only knew how many people or robots register here on a daily basis to post link spam comments (most of them) or to create fake puppet accounts to post to shill local businesses (many) or to drum up stories for the local magazines or gossip sites (some) or just to have a fake new account to argue with others (some).

We get only about 10 of the above on a daily basis due to the success of software measures put in place to make this more difficult to get away with. Used to be much worse.

Anyhow, it's a constant process and we do our best to nip the bad ones at the bud as they show up and exhibit known patterns or attributes.

Most of this happens pretty quickly, as new accounts appear all day long and those with questionable attributes are vetted and dealt with as needed out of view of most of the public.

But yeah, that's just how the Brooklynian sausage is made, and the boards kept as free as possible of (or made aware of, in some cases) the various creeps out there that would flood this place with their junk.