WHEN JESSICA AND I finally arrive, after 10 p.m. on a recent Saturday, we try to act like everything is normal.

Everything is not normal.

We’re not only later than we said we’d be. We’ve arrived at the party on the wrong night.

Yesterday was the guy’s birthday. Yesterday was the guy’s birthday party.

And we knew it.

Which is to say, we sorta knew it. I mean, yes, in the most strict and literal reading of the situation, we did know it at the hour that we knocked on their door. But we didn’t know it as of a month or a week or even a day ago. I learned that we missed his party when I was talking to the guy’s wife on the phone earlier in the day.

“We missed you last night,” she said.

“What do you mean?” I said. “I thought the party was tonight.”

“No,” she replied. “I called you.”

“Called me? When?”

“I called you a few times. I left a message.”

“We don’t have a message,” I said. “We have no message.”

“Well, I left one.”

“I didn’t get one till yesterday, and that was from your husband. He said the party was tomorrow, which means today.”

I was feeling increasingly weird.

How could there be this miscommunication? She said she left a message. We say we never got one.

“I don’t know why he said that,” she replies. “But come tonight anyway. There is still family here. They’d love to see you.”

“The thing is, I was calling because we have a deal tonight,” I said.

“You always have a deal,” she responded, and laughed.

I feel like a schmuck. She’s right. We do always have a deal, or a thing, or a something-or-other. It’s not that we lead extravagantly busy social lives. We don’t. In fact, most weekends, one of us can be found in front of an array of videos at the local video-rental store, calling the house to ask the other, “What did we say we wanted to rent the next time we got a movie?” Yet, somehow, there do seem to be a lot of … things.

And here was one, a get-together with people who had been to South Africa, where we were contemplating going. They would be cooking food, showing photos, providing background. It couldn’t be rescheduled. Fortunately, it started at 6:30 p.m., early enough to get over to the house of last night’s party relatively early.

“Well,” I said, flustered, “I was just calling to say that we were going to be late tonight.”

“No problem,” she said. “When do you think you’ll get here?”

“Probably 8:30 or nine,” I said.

“Ohhh,” she said. “No problem. See you then.”

“Don’t cook,” I said. “We’ll have eaten.”

She is a phenomenal cook and a gracious hostess, and it pains her if someone comes to her house and doesn’t eat. But I feel we’ve caused enough problems, and I don’t want her to go to any trouble.

“Just come,” she said, and I know that this means she’ll cook.

“We’ll come,” I said. “Just don’t cook.”

I got off the phone and turned to Jessica.

“I can’t believe this,” I said. “The party was last night.”

“Last night?” she said.

“She says she called. Did we get a message from her?”

“No,” Jessica said. “Maybe she called our old number.”

“By now, I’m sure that number wouldn’t work,” I said.

“Did she call your cell?”

“No,” I said. “I’ve been on it all week. I’d know.”

I TRY TO figure out what happened.

“I wish she had e-mailed,” I say, finally.

“We’d have gotten an e-mail. And now everything is all weird. She thinks she called us, and we think she didn’t. We think she didn’t invite us, and she thinks she did.”

I pace, which, aside from eating, is my favorite coping mechanism when I’m fretful.

“I feel like a schmo,” I continue. “It’s the guy’s 50th. I feel terrible. We missed it. Now, we’re trying to make it up to each other by going on the night when they’re not having the party.”

“This is like a Curb Your Enthusiasm episode I saw,” a friend tells me. “Except he [Larry David] tried to get out of going to the party by pretending he forgot which night the party was.”

So, now I’m really freaked. What if they have HBO? What if they’ve seen that episode? What if they think I pulled a Larry David?

And so here we are, knocking on the door of a house where the party was held the night before. A night, by the way, that we didn’t have a deal or a thing or a something-or-other. And not only are we here on the wrong night, but we’re also an hour late. That would not have mattered last night when the party was actually held. Their parties go into the wee hours. But, now, the night after the party, I am feeling like a trespasser.

The next day, we check the answering machine. I’ve been traveling, and Jessica has been working late. Maybe there is a message that our teenage son listened to and forgot to tell us about.

We play back the messages.

Sure enough, there it is. Her voice, saying: Party. Friday night.

After hers, his, saying the second part of the party is Saturday night. We thought he meant that the first part was her birthday party a month earlier.

Turns out … oh, never mind!