I'm not a full-time software guy. In fact, in the last ten years, 90 % of my work was either on the hardware or doing low-level (embedded) code.
But the other 10% involves writing shell scripts for development tools, making kernel changes to add special features, and writing GUI applications for end-users.
The problem is that I find myself facing significant holes in my knowledge, often because it's been years since I've done "X", and I've either forgotten, or the environment has changed.
Every so often, there are threads on TheDailyWTF.com along the lines of "WTF: the guy spent all day writing tons of code, when he could have called foobar() in library baz". I've been there myself, because I don't remember much beyond the #include <stdio.h> stuff (for example), and my quick search somehow missed the right library.
What methods have you found effective to crash-learn and/or crash-refresh yourself in programming environments that you rarely touch?