It would be natural for an American Jew noticing that Nov. 28 marks Thanksgiving as well as the first day of Chanukah to take the opportunity to plan an extra special family gathering. But Dana Gitell took things much further.
A marketing professional living in Norwood, Mass., Gitell coined and trademarked the word “Thanksgivukkah,” launched a website  as well as Facebook  and Twitter  pages for the joint holiday, and partnered with Judaica retailer ModernTribe.com on a line of t-shirts and greeting cards to mark the occasion — one that, according to one analysis of the Jewish and Gregorian calendars, won’t occur again for more than 70,000 years.
Gitell, who had known “Thanksgivukkah” was coming for five years, said the more she thought about it, the more she came to appreciate the significance behind the overlap of two holidays that “both celebrate religious freedom."
“You can celebrate Judaism, you can celebrate America, and you celebrate the Jewish-American experience on the same day, because how would this be possible if we didn’t have a country as free and as welcoming as America?” Gitell said.
Exactly how rare is Thanksgivukkah? Gitell did her due diligence through online research and taking a stab at the math herself, but said she ultimately leaves such matters “to the scientists.” Enter Jonathan Mizrahi, who has a Ph.D. in physics from the University of Maryland and currently works for Sandia National Laboratories in Albuquerque, NM. Mizrahi used the math software program Mathematica to chart the futures of the Jewish and Gregorian calendars, and the output “produced no results other than this year.”
“I thought I made an error in the program, and I checked what I’d done, and everything seemed okay, and I pushed the year out further and further and further… and it still was telling me that it wasn’t ever going to happen,” Mizrahi said.
According to an analysis  posted online by Mizrahi, the Jewish calendar “is very slowly getting out of sync with the solar calendar, at a rate of four days per 1,000 years.”
“This means that while presently Chanukah can be as early as Nov. 28, over the years the calendar will drift forward, such that the earliest Chanukah can be is Nov. 29,” Mizrahi wrote. “The last time Chanukah falls on Nov. 28 is 2146 (which happens to be a Monday). Therefore, 2013 is the only time Chanukah will ever overlap with Thanksgiving.”
“Of course, if the Jewish calendar is never modified in any way, then it will slowly move forward through the Gregorian calendar, until it loops all the way back to where it is now. So, Chanukah will again fall on Thursday, Nov. 28... in the year 79811,” he added.
Gitell got enthusiastic feedback when she started posting juxtapositions and mashups of different cultural aspects from Thanksgiving and Chanukah online.
“So many people that I talked to, many who aren’t Jewish, think it’s exciting and funny,” she said.
After creating the Thanksgivukkah Facebook page with her sister Deborah, Gitell worked with graphic illustrator Kim DeMarco to design t-shirts and greeting cards. She approached ModernTribe.com about being the retailer and said she got an email response within five minutes.
“I knew that a collaboration to create Thanksgivukkah items was a perfect match for our mission to create ways for modern Jews to express their faith and keep our traditions alive, meaningful and fun,” Jennie Rivlin Roberts, president of ModernTribe.com, said in a statement.
The ModernTribe.com Thanksgivukkah merchandise employs the slogan “Light, Liberty & Latkes.” Ten percent of the proceeds will benefit the nonprofit MAZON: A Jewish Response to Hunger.
“I felt like [Thanksgivukkah is] almost like a Woodstock-like event, we can tell our kids, ‘I was there, I lived through Thanksgivukkah. I remember that day, it will never happen again,' " Gitell said. "So that gave me the idea for something akin to a concert t-shirt, expressing that you were there, you lived through it, as a memento."
Gitell said her childhood in Squirrel Hill, Pa., a neighborhood of Pittsburgh with a significant Jewish population, colored her passion for the Thanksgivukkah project.
Squirrel Hill "was a place where most kids were Jewish, and people who weren’t Jewish, they felt left out,” she said. “Non-Jews wanted to have their own Bar Mitzvah in middle school. That’s the kind of experience that probably could only happen in America.”
While American Jews prepare for Thanksgivukkah, whether or not 2013 is the first-ever occurrence of the “holiday” is up for debate. In 1863, President Abraham Lincoln enacted Thanksgiving to fall on the last Thursday in November. But Thanksgiving was changed to the fourth Thursday of November — not necessarily the last Thursday — in 1942 under President Franklin Delano Roosevelt, a move intended to extend the holiday shopping season. Using the former date of America’s Thanksgiving, the last Thursday of November, Thanksgivukkah would have occurred in 1888, according to Mizrahi.
Thanksgivukkah’s frequency can also depend on whether the first night or the first day of Chanukah is used as an indicator. This year, the first candles are lit the night of Nov. 27, while the first full day of the holiday is Nov. 28, corresponding with Thanksgiving. According to an analysis by Eli Lansey, who has a Ph.D. in physics from the City University of New York and like Mizrahi used the Mathematica software program, the first night of Chanukah will correspond with Thanksgiving in the years 2070 and 2165 — much sooner than 79811, the next time Mizrahi said Thanksgiving would fall on the first day of Chanukah.
No matter what metric one uses, Thanksgivukkah has garnered a significant following. Mizrahi’s mathematical analysis garnered about 100,000 page views online, to his “utter amazement.”
“When I first did this, I thought it was interesting, but I did not expect anywhere near the response I got,” Mizrahi said.