I've always found the technical practices advocated in Agile software development to be fascinating; especially, some that were started or popularized by Extreme Programming, such as test-driven development (TDD), refactoring and pair programming.
A technical practice that has recently caught my attention is mob programming. More and more developers I follow on social media have been talking about it favorably, to the extent that I thought, "Maybe I should look into this." I dipped my toe in the water (so to speak) back in April with a free session offered by Bob Allen, an Agile technical coach. It was a lot of fun.
What started as a curiosity turned out to be a great collaboration, TDD and refactoring learning opportunity all rolled up into one. I plan to look deeper into mob programming, sharing my learnings as I go. We'll see what comes of it.