Rare is the day that Joe Biden doesn’t tell a lie or garble a sentence, but even by his standards, this week was a mess — featuring ramblings in Vietnam, fibs about where he was around 9/11, claims he taught Ivy Leaguers political theory, and more.

The horror show kicked off in Hanoi, Vietnam on Sunday when the 80-year-old commander-in-chief began a press conference by forgetting that a classic Robin Williams film was, you know, a film.

“One of my coworkers said, ‘Remember the famous song ‘Good Morning Vietnam?’ Well, good evening, Vietnam,’” Biden said, before going on to discourse about John Wayne as he discussed climate change, a major topic at the G20 summit the president had attended in India.

“And the Indian looks at John Wayne and points to the Union soldier and says, ‘He’s a lying, dog-faced pony soldier,’” said Biden, recycling one of his favorite lines from the campaign trail. “Well, there’s a lot of lying, dog-faced pony soldiers out there about global warming. But not anymore.”

Biden then appeared confused about the number of questions he was scheduled to take from reporters at Hanoi.

“Staff, is there anybody I haven’t spoken to?” he asked before snapping at one tenacious journalist: “I ain’t calling on ya! I’m calling on — it says I have five questions!”

The whole sordid affair was cut off by press secretary Karine Jean-Pierre after just 26 minutes, with Biden signing off by telling a global audience: “I tell you what, I don’t know about you, but I’m going to go to bed.”

On Monday, Biden spoke at a 9/11 commemoration ceremony in Alaska, where he incorrectly claimed he was at Ground Zero one day after the terrorist attack on Lower Manhattan.

“And I remember standing there the next day and looking at the building,” he said. “I felt like I was looking through the gates of hell, it looked so devastated because of the way you could — from where you could stand.”

The president, however, was not there on Sept. 12, but on Sept. 20. In his own memoir, “Promises to Keep,” Biden revealed that on the day after 9/11, he was actually in Washington presiding over business on the Senate floor.

After a quiet Wednesday, Biden resumed his fibbing Thursday, telling lies to Maryland students and rabbis alike.

The president started his day by fondly recalling during a speech at Prince George’s Community College that “I taught at the University of Pennsylvania for four years and I used to teach political theory. And folks, you always hear, every generation has to fight for democracy.”

One problem: Biden never actually taught a single course at Penn and only made nine reported visits to the Philadelphia campus despite raking in nearly $1 million from the university between 2017 and 2019.

The president started his day by fondly recalling during a speech at Prince George’s Community College that “I taught at the University of Pennsylvania for four years and I used to teach political theory. And folks, you always hear, every generation has to fight for democracy.”

The gaffes at the school didn’t end there, as Biden suggested African American and Hispanic workers don’t have “high school diplomas” before the White House’s official transcript tried to clean up his words.

“We’ve seen record lows in unemployment particularly — and I’ve focused on this my whole career — particularly for African-Americans and Hispanic workers and veterans, you know, the workers without high school diplomas,” the president said in televised remarks.

However, according to the official transcript, Biden was supposed to include the word “and” to separate the African-Americans, Hispanic workers and veterans from those without high school diplomas.

In the evening, the president held a call ahead of this weekend’s celebration of Rosh Hashanah, the Jewish new year, where he again got loose with the truth in order to cozy up to rabbis.

“I, you might say, was raised in the synagogues of my state. You think I’m kidding, I’m not,” claimed Biden, America’s second-ever Roman Catholic president.

The 80-year-old cited the Beth Shalom congregation in Wilmington, Del., as “the home of countless friends for me.”

Biden’s memoirs, however, lack any details about such ties, with the latest claim suspiciously resembling his assertion from last year that he was practically “raised in the Puerto Rican community at home.”