C# tuples are a new feature of C# 7 that allow creating anonymous types with richer information. They are similar to anonymous objects but provide more type safety and flexibility, making it easier to return and pass data as a single unit. The syntax for tuples is to put parentheses around a comma-separated list of types and names, allowing for easy creation of classes on the fly without defining them explicitly. Tuples can be used in methods as both return types and parameter types, providing a convenient way to handle complex data structures. The author demonstrates their use with a simple console app that interacts with Couchbase, showcasing how tuples can be used to get and insert documents into a database.