Same story: C++ at school and VB then eventually C# at work. About 7 years into my career, I started feeling as though I had stagnated. Over the past 4 years, I

Same story: C++ at school and VB then eventually C# at work. About 7 years into my career, I started feeling as though I had stagnated. Over the past 4 years, I took the time to learn Ruby (RoR), Scala, some Clojure, Nim, and now, some F#. Each of them has, in some way, made me a better C# programmer. I can't go out and interview for a position programming any of these languages, but they aren't blindspots for me either anymore. I would suggest picking a language you have an interest in and a project you have an interest in and having a go at it. Then repeat the process with a new language and a new project. At the end, you will have some working software and an expanded perspective.