Jon Thomas Rietzke, a young man from the Midwest, came east in the 1950s to attend Villanova University and later work for IBM. His new wife, Mary, introduced him to one of the seasonal traditions of her native Philadelphia: the annual trip to Ocean City.

And what started quietly enough about 50 years ago became the big, loud, crazy and fun family reunion that rolled into town this week. The family's annual Ocean City vacation has grown to include 40 to 50 friends and family housed in five vacation rental units on the 4800 block of Central and Asbury avenues. The family arrives from Boston, Chicago, Omaha, Toledo, Tampa and a lot of points in between.

"It’s funny how we all live 51 weeks a year in different places, in different states, but mention “the shore,” and we all have that common experience, and it’s as if we are all “from” there," said Laurie Moynihan, a niece of Rietzke.

The Rietzke's annual tradition defines a growing trend in Ocean City. As time and distance separate family members in a mobile society, Ocean City is becoming one of the constants in the lives of many families.

"It just goes back to that family type of feeling," said Gary Jessel, owner of Fox Real Estate, the agency that placed the Rietzke clan in the adjacent rental units. "People experience it through their parents and their parents' parents. That's what feeds our tourism cycle."

Jessel said the "reunion" that brings together multiple generations of families from across the country has been part of a long trend in the resort. Even on his home block on the north end of town, Jessel said he was surrounded this week by an extended family that wanted to be within walking distance of the same front porch.

For the Rietzke clan, the Ocean City vacation has seen its share of big moments: a wedding, a baptism and two marriage proposals among them. But the nights sitting on the porch and feeling an ocean breeze are just as memorable.

The family's vacations follow a similar pattern from year to year in Ocean City's Saturday-to-Saturday vacation rental cycle.

Saturdays are "pizza night" with the family members arriving at different times during the day and settling in. Throughout the island, a new wave of vacationers is doing the same thing on Saturdays, giving Ocean City a schedule of its own.

"Saturday night is not the busiest night," said Bill McGinnity, the owner of Cousin's Restaurant and vice president of the Ocean City Restaurant Association. 

But McGinnity said local restaurants have to prepare for a crush that can happen during any other day of the week.

For the next five nights among the Rietzke clan, each house will take a turn hosting dinner for everybody.

While the younger generations take the trolley service to the Ocean City Boardwalk at night, the family always has at least one car heading to the Atlantic City casinos — sometimes two (with one group returning early and one late).

"Maybe 2012 will be the year for someone in the group to win “the BIG one,” Mary Lee Rietzke said.

The family might start a day with a baseball game on the beach and end it with another tradition tie-dying T-shirts. The group stakes a claim on a large part of the beach at 48th Street every day.

Among the vacationing family were 10 people under the age of 12 — the next generation to bring future wives and children back to Ocean City. That sort of exponential growth is what fuels a local economy that fills more than 5,000 rental units for most weeks of the summer.

I thought someone might like to publish the fact that Ocean City has been able to keep one family coming back for over 25 years," Moynihan said. "To let people know there is an alternative to "The Jersey Shore."