How do you measure the greatness of a joke?

I have no idea, but a joke must be pretty damn good if it sticks in your brain, along with exactly what you were doing at the time you heard it—kind of like the news of a disaster… without the disaster part.

When I read this particular Jess Dweck (@TheDweck) Twitter joke—on August 28—I was with my friend Theresa and her little daughter in Chicago’s Children’s Museum on Navy Pier. The daughter was playing in a room full of hundreds of stuffed animals. I assume this room was designed to teach children how easy it is to spread germs. I almost felt like a parent myself, since I was ignoring a child while checking my phone: specifically, for information on Syria, whose recent use of chemical weapons made war seem imminent.

Like so many clueless folks, my friend and I didn’t know diddlysquat about Syria, and I was trying to bring our knowledge level up to a smidgen or a clue. While searching Twitter for (I swear) links to actual news, I spied this joke by Jess Dweck, which, for me, is her Best Joke Ever:

“Attacking Syria is risky, but if we go to war with another Middle Eastern country, we get a free sub!!”

As the kids and morons say, I LOL’d at that one—repeatedly. I showed Theresa. I starred and retweeted it. In subsequent days, I repeated it to friends. When a joke has that kind of impact, it’s perfect.

Of course, this joke isn’t entirely original, but then again, few jokes are. The “get a free sub” idea has been the basis of many jokes over the years. Besides being an actual thing, the concept was spread by “The Strike,” a 1997 Seinfeld episode better known for introducing the holiday of Festivus. One of that episode’s plots is Elaine trying to get back her sub card, which she had foolishly used to write a fake phone number for a wooer in a denim vest. We’ve all been there. That sub card, along with the free sub, became Elaine’s white whale.

The first place I can remember hearing or seeing the free-sub idea used as a joke format was on Arrested Development. In the 2005 episode, “Making a Stand,” Michael Bluth realizes his mother Lucille is getting her bazillionth plastic surgery and deadpans, “I see; the apartment’s not the only thing getting a facelift. I hope you kept your punch card. You’re about due for a free one.”

As with every joke formula, variations abound on Twitter, many dealing with abortion, like this tweet by @raptor_math (“I’ve got 2 more punches on my abortion punch card before I get a free one. #ExposePP”) that satirized the demonization of Planned Parenthood. I enjoyed this recent spin by TV critic Maureen Ryan: “999 comments on my ‘Walter White: Not a hero’ piece. Just one more person telling me I’m doing it wrong and I get a free chamomile tea!” These examples (and Dweck’s) show that no matter how common the joke formula, there’s always a new twist.

Another thing I like about this joke is that Dweck might be as clueless as I was (and still mostly am) about Syria. Dweck is not only making fun of the fact that the U.S. goes through Middle Eastern wars like my mom goes through books about Princess Diana: she’s making fun of the fact that the average person knows so little about Syria that an international invasion punch-card might be a plausible pretext for war.

I also admire Dweck’s ability to write a memorable, funny topical joke on a tricky subject. On Twitter, topical jokes can be exhausting, as every news story goes from “That happened?” to “Ugh, I’m sick of hearing about that” in about 20 minutes. Crafting a non-groaner with a fresh take on something everyone is writing about is tough. The difficulty is multiplied when it’s a delicate topic. The gassing of Syrian children isn’t exactly a natural knee-slapper.

But as the late George Carlin said—and The Onion has proved, especially with their first issue after 9/11—you really can joke about anything, as long as you’re aiming at an appropriate target. New Yorker TV critic Emily Nussbaum summed up this notion recently: “To modern joke critics, the key distinction between a good joke and a bad one is supposed to be between ‘punching up’ and ‘punching down’—taking a cheap shot at someone who is already weaker than you.” Dweck punches at the U.S. and herself—two appropriate subjects. That’s a smart joke.

There’s plenty more to enjoy from Dweck. She writes for Jimmy Fallon and has an understated joke style that reminds me a little of Julius Sharpe, another excellent TV writer, standup comedian, and Twitter comic. I like the weariness behind this recent Dweck tweet: “I don’t know what’s more upsetting, that people are making racist comments about Miss America or that there’s still a Miss America.” She’s equally good at making fun of pop culture (“Lady Gaga is Walmart-brand Bjork.”) and thoughtless comments (“When someone says, ‘I saw a fat version of you,’ what they’re basically saying is, ‘I saw a fat person and thought of you.’”). She even has unique insight into puppetry: “’I don’t do anal.’ -Unsuccessful puppet.” Wonderfully, her Twitter feed is uncluttered with annoying @ replies, so you can just read joke after joke. She’s a keeper.

In fact, I’d say Dweck is one good joke away from getting a free unsuccessful puppet.