Apparently it's possible to create structs and unions in C that allocate an exact number of bits to each field. These structures are called bitfields. An informal survey of some programmers I know indicates that even people who write a lot of C++ and C may not have seen these before. For those times when every bit matters, these could save a lot of ugly shifting code.

A friend of mine recent mentioned Python generators. I looked them up and they're pretty neat. They let you generate streams of data on an as-needed basis without complex state machines. If you haven't seen Python generators before, take a look a this article.