During the summer and fall of 2026 I operated a ‘pop-up classroom’ booth during street fairs in Boston. The idea was to engage people in a fun/informal way and teach them something interesting and important. Over the course of three events, I estimate I interacted with 300-500 people. It was a lot of fun for me and I am convinced that street fairs provide an untapped pedagogical opportunity. In this post, I will describe what I think this opportunity is, what I did and tips for you to implement this in your local community.
Street fairs as a pedagogical opportunity
The general thesis is that most people enjoy learning but often not in traditional classroom environments. Lets compare a street fair to a traditional K-12 or university classroom.
Environment: A street fair is outside, there may be music playing, people are standing and walking - it is fun. In contrast, in traditional classrooms, students are inside and sedentary - it feels stiff.
Fully opt-in: People walking up to my booth choose to be there and can leave at any time. In traditional classrooms, students are often forced to attend class or must take certain courses.
Direct physical conversations: No lecturing at a distance! All learning takes place face-to-face in conversational style.
Small class sizes: I usually interacted with 1-2 people at a time (max 5).
Diverse backgrounds: You never know who’s going to walk up to your booth.
No formal constraints: No fixed curriculum, no assessments required - the pop-up classroom is whatever you want it to be!
Limited engagement time: The typical engagement time was 1-5 minutes.
What can you teach at a street fair?
Given these features and constraints, I designed my curriculum to contain the following elements:
A hook. I needed a way to get people off the street and into my classroom
Fun, bite-sized tidbits that
Can be understood by a broad audience
Can be explained in ~1 minute
Can leave long-term impressions
A final message that can be summarized in a few words.
My initial focus was on mathematical literacy, but I believe the same elements can be applied to other disciplines.
A focus on mathematical literacy
In my initial prototyping I focused on mathematical literacy. In particular my goal was to train people to ask two questions:
“What does that number mean?”
“What is the null model?” (or “what would you expect by random chance?”)
I think this curricular setup is successful because it is
Possible to train people to ask these questions
These questions can be answered by internet search or AI systems.
Thus you just need to get people asking these questions and the rest happens naturally.
The curriculum
The birthday problem (the hook)
The setup is a set of calendars printed on 40” x 30” paper. People would mark their birthdays on the calendar and once a date was marked twice I would stop and flip to a new calendar page.
This is the hook to corral people off the street and get them talking to me. I would shamelessly ask people walking by, “would you like to play the birthday game? Just mark your birthday’s on the calendar”, with a success rate of about 50%. Over the course of three events I went through 13 calendar pages with a total of 335 markings (distribution: 34, 17, 12, 35, 15, 43, 5, 27, 25, 32, 29, 29, 32).
Beyond the hook, the goal of the birthday problem was to show people that probabilistic results could be counterintuitive. It was also a great segue into the next part of the curriculum. Rarely did I get into the birthday problem math.
What does that number mean?
The setup here is a set of questions printed on foam board. In practice I almost always started with the weather question, then moved to the COVID question. The question about what does a 50% chance of getting a head from a fair coin is too philosophical. Another good one is SPF for sunscreen. I would also ask people what numbers were on their mind and typical conversations topics were interest rates, gambling, polling etc.
“What does that number mean?” is not a simple question. In practice I focused on “how is that number arrived at (or calculated)?”. Then I emphasized that 80% chance of rain is a forward prediction, whereas vaccine is 95% effective is a retrospective analysis. I will have more to say on this in a future post.
The point here is that numbers are often quoted without explanation. More generally, people say numbers without knowing what they mean. This is bad. Again, the point of this exercise is just training people to ask the question, “what does that number mean?”.
Mapping probabilities to words
The setup here is a graph showing how different organizations map probabilities to words. Sources: EU Pharma (pdf), IPCC (pdf), UK Intelligence Assessment
This one is fairly self-explanatory. Instead of asking “what does that number mean?”, this poster trains people to ask, “what exactly does [rarely, common, unlikely, etc] mean?”.
Coin flipping exercise
The next two items are intended to train people to ask, “What is the null model?”. This task is more involved than “what does that number mean?” but it was still reasonably successful. The setup here is a reasoning exercise printed on foam board.
Apple’s ‘smart shuffle’
The setup here is a poster printed on foam board. The message is that humans are not very good at reasoning about randomness - but I firmly believe this reasoning can be improved through training!
Video of Steve Jobs talking about ‘Smart Shuffle’ (starts at 11:49).
The Monty-Hall problem
This is a tough one. It requires a lot of time/attention and is difficult to explain. I only did this twice and it didn’t fit with the goal of the classroom (which is to emphasize the two questions). I think this is best left for more intimate gatherings. If you really want to try this at a street fair, I would recommend practicing **a lot** beforehand. I also like the version with more than three cups (eg. start with five cups and flip over three empty ones).
Doing this in your community
Here are some practical tips for doing this in your community:
Have more than one person. The most successful model was were one person was manning the ‘hook’ and another was engaging in longer term conversations. (Thanks to Ben, Daniel, Alex and Amith for the help!)
Have a wind strategy. A foam board on an easel is basically a sail. It will tip over under moderate wind gusts (you can use AI to help you calculate). I used a combination of weights, tape and bungee cords to hold everything together.
Be prepared to improvise
Cost
Excluding tent and signage (which I think are superfluous) my setup cost about $500. This is almost entirely fixed cost, the only variable cost is the calendar pages. The cost breakdown is:
Posters: 4 foam board posters averaging 20” x 30”. Commercial printers in my area charge about 10 cents per square inch so thats $60 per poster. I used this easel which costs $15. So a total of $75 per poster is $300 overall.
Birthday problem: A 29” x 39” calendar printed on blueprint paper costs about $6 at a commercial printer. How many of these you go through will depend on flow rate at your fair, time spent at fair and whether you have someone dedicated to manning the calendar. I averaged 3-6 per event. So lets say 15 calendars at $6 is $90. I attached these calendars to a 30” x 40” foam board ($20) using large binder clips and clamped this to a larger easel (this one, $80). So total cost for birthday problem is around $200. This does not include odds and ends such as markers, binder clips and clamps.
Tent, signage, wagon, table, chairs etc will add cost. In practice I found a table to be useful. A chair sounds nice, but I was on my feet for the entire event!
Downloading the curriculum
I am releasing the files contained in this post under a CC BY Creative Commons license.
Contact
Please contact me if you use this curriculum at an event, are inspired to do a pop-up classroom with another curriculum, would like to do a pop-up classroom but do not have the funds or if you just think this is interesting!