"@davidjmalan, who has taught @CS50 every year since 2007, is on sabbatical, with computer science lecturer Henry H. Leitner taking over as the course changes its lecture format, assessments, and grading structure." thecrimson.com/article/2026/…

Introducing Classroom 50, classroom50.org, a free and open-source tool for managing and grading programming assignments via @GitHub. Supported by the Fifty Foundation, fifty.foundation, GitHub's official open-source partner. Learn more at github.com/foundation50/clas….

💻 @cs50: Led by David J. Malan, a Harvard University computer science professor making coding approachable for everyone.

Have you registered for CS50x Puzzle Day 2026 yet? It starts anytime after 00:00 on Friday, April 3, and ends anytime before 23:59 on Monday, April 6, in your own time zone. Register at cs50.ly/register. Learn more about Puzzle Day from Professor @davidjmalan. 👇

Hello, world! CS50x Puzzle Day starts anytime after 00:00 on Friday, April 3, and ends anytime before 23:59 on Monday, April 6, in your own time zone. Register at cs50.ly/register. CS50x Puzzle Day is an online adaptation of an event we hold at Harvard each year, an opportunity to collaborate on a team with classmates, family, friends, students, and colleagues on a packet of puzzles (i.e., logic problems). The event is open to everyone around the world, whether taking CS50 or not. No prior CS experience required. Teams of size 2, 3, or 4 are encouraged, or you can participate on your own. Teachers are welcome to host their own version during class. See cs50.ly/puzzle-day-2025 for a summary of last year’s CS50x Puzzle Day as well as some past puzzles for practice. Indeed, the best way to practice for this year is to solve past puzzles first!

This is Lecture 0 (the very first!) of @CS50 for Business, in which you'll learn all about Interpreting Information. Discover the fundamentals of computer science, from binary data to algorithms, and learn how technology processes information to solve real-world problems efficiently. To take this course for a certificate, register at cs50.edx.org/business. piped.video/pWPHa4FL264

CS50 is back with a new-and-improved course, Computer Science for Business! This 9-lecture series is designed specifically for business professionals, managers, founders, and decision-makers. Tune in every day on @CS50’s YouTube at 9:00 am ET starting tomorrow. To take this course for a certificate, register at cs50.edx.org/business. And for now — a word of introduction from Professor @davidjmalan. piped.video/tT9VMlXRkwE

"In this episode, we explore Professor @davidjmalan's journey into computer science, why discovering a subject later can be a strength, and how curiosity often matters more than credentials. We talk openly about imposter syndrome, the role of struggle in real learning, and what education should protect in an age of AI. Along the way, Prof. Malan reflects on the power of computer science to turn people from consumers into creators, and the responsibility educators have as technology continues to evolve." With Yash Shah of @imperialcollege. piped.video/watch?v=EgEL3dlL…

You're invited... a @CS50 lecture on #AI with Prof. @davidjmalan in Seattle, Washington, USA, on Thursday, February 12, 2026, 5:45pm to 8:30pm PST. "Please join us for an in-person look at how CS50 has incorporated Artificial Intelligence (AI), including its new-and-improved rubber duck debugger, and how it has impacted the course already. CS50 is Harvard University's introduction to the intellectual enterprises of computer science and the art of programming, freely available as OpenCourseWare, with more than 7M registrants on @edXOnline and 2.2M subscribers on @YouTube." Register to attend in person (only) at eventbrite.com/e/using-ai-as…. #education #community

Now live on @edXOnline, this is CS50x 2026, @CS50's (free) introduction to the intellectual enterprises of computer science and the art of programming, including AI. Open to anyone online. Register at cs50.edx.org/. #education #community

Live at 00:00 UTC, this is CS50x 2026... piped.video/watch?v=UuIEbpQm… #education #community

Happy holidays from Professor @davidjmalan and @CS50’s whole team here in Cambridge. 🎁 Stay tuned for release of CS50x 2026 on January 1, 2026.

This is CS50x 2026 with @davidjmalan, @CS50's (free) introduction to the intellectual enterprises of computer science and the art of programming, now with artificial intelligence (AI). 🦆 Full season available on @edXOnline on January 1, 2026. Register at cs50.edx.org. #education #community #stranger #things

A very happy Thanksgiving from (and to!) @CS50’s whole team at @harvard, @OxLifelongLearn, and beyond! 🧡🍂🥧 Artwork by Sophie Anderson. #education #community #thanksgiving

Live from @Harvard University at 1:30pm EST with Professor @davidjmalan, this is @CS50's last lecture this year. Open to anyone online. This lecture will become part of CS50x 2026 on @edXOnline on January 1, 2026. On @YouTube at piped.video/live/NcBMUE1fNRw. On @Zoom at cs50.zoom.us/meeting/registe….

Exams with More Learning and Less Stress with a Computer-Based Testing Facility, a @CS50 Tech Talk at @Harvard with Prof. Craig Zilles of @UofIllinois. piped.video/watch?v=Vkh9gT7K… ``Exams are an important tool for summative assessment, whose utility has only grown with the advent of large language models (LLMs) like ChatGPT, because they can be implemented in a trustworthy manner. But exams are generally not well liked by either students or faculty. Students find them stressful. For faculty (and their course staff), they represent a large administrative burden to write, proctor, and grade. This large burden means they are done infrequently in many classes, but this infrequent testing encourages cramming and leads to high test anxiety. In this talk, I'll share (1) research on the benefits of frequent testing and "second-chance testing" (optional exam re-takes) on increased student learning and decreased test anxiety, (2) research on patterns of cheating on unproctored online assessments, and (3) how we've reduced the instructor workload at Illinois to implement frequent testing through our Computer-based Testing Facility (CBTF). The CBTF is a collection of proctored computer labs that, in conjunction with the PrairieLearn open-source question-asking platform, enable our faculty to run sophisticated exams with almost no recurring effort even in the largest classrooms. For example, our CS 1 course for majors (run by a single faculty member) ran weekly exams for 1,150 students. Key enabling ideas for the CBTF include: (1) sophisticated auto-grading questions, (2) question generators, (3) asynchronous exams, and (4) dedicated testing space and proctors. The CBTF has been running for over 10 years and proctored over 100,000 exams last semester.'' #education #community

Live from @Harvard at 1:30pm EST, this is Week 8 of @CS50 on HTTP, HTML, CSS, and JavaScript. Open to anyone online. This lecture will become part of CS50x 2026 on @edXOnline on January 1, 2026. On @Zoom at cs50.zoom.us/meeting/registe…. On @YouTube at piped.video/live/gPCuN4WfTgc. #education #community

Live from @Harvard at 12pm EDT, this is @CS50's lecture on #AI. Open to anyone online. This lecture will become part of CS50x 2026 on @edXOnline on January 1, 2026. On @Zoom at cs50.zoom.us/meeting/registe…. On @YouTube at piped.video/live/yD1Y1chp5R4. #education #community

Live from @Harvard at 1:30pm EDT, this is Week 5 of @CS50 on data structures and more. Open to anyone online. This lecture will become part of CS50x 2026 on @edXOnline on January 1, 2026. To attend in person some day, see cs50.ly/attend. On @Zoom at cs50.zoom.us/meeting/registe…. On @YouTube at piped.video/live/Sca41aXoj5U. #education #community