CS50 Puzzle Day
2026-09-05T12:00:00-04:00/2026-09-05T16:00:00-04:00
Science & Engineering Complex
150 Western Ave, Allston MA 02134
4 hours of pizza, puzzles and prizes! Plus a free CS50 Puzzle Day t-shirt! 👕
CS50 Puzzle Day is an opportunity to collaborate on a team with classmates and friends on a packet of puzzles (i.e., logic problems). Among the event’s goals is to send a message that computer science is more about problem-solving than it is about, say, programming. Among the event’s other goals are prizes.
Teams of size 2, 3, and 4 allowed. Open to all Harvard (and MIT) affiliates, whether taking CS50 or not.
Puzzles are not programming challenges. No prior CS or programming experience needed, just logic and smarts! See some past puzzles.
How to Get There
Science & Engineering Complex (SEC)
150 Western Ave, Allston MA 02134
Past Photos
What to Bring
- Laptop with charger
- Pen/pencil
- Scratch paper
How to Prepare
No preparation (or prior background or experience of any sort!) is expected. But you might find it helpful to peruse some past puzzles!
Past Puzzles
Here are (some of) Fall 2025’s puzzles and walkthroughs of solutions as well as Fall 2024’s puzzles and walkthroughs of solutions!
Teammate Finder
Need a hand finding teammates? Add yourself to the spreadsheet at cs50.ly/teammates, keep an eye on it for others’ additions, and email anyone with whom you might like to form a team! A friendly “hey, like to work on a team together” email, with a little bit about yourself, should suffice to break the ice!
Past Quotes
- “Find some friends and try your best!”
- “Great fun, mind boggling, and such a great team activity!”
- “Get ready to squeeze that brain juice dry!”
- “Don’t be intimidated if you aren’t a ‘coder.’ As a chemistry lecturer and an AI student, we found that logic is a universal language. The best part isn’t just finding the answer; it’s the ‘bonding’ moment when two different ways of thinking finally click together.”
- “Embrace the ‘aha!’ moments and don’t be afraid to think outside the box!”
- “It’s all about teamwork.”
- “A fun and challenging experience that pushes your problem-solving skills while making learning feel like a game.”
Acknowledgements
Special thanks to CS50’s alumni and friends at Meta for writing this year’s puzzles!