We have a little less than a month before our two-year anniversary, so I thought we might do a fun little activity: post your most basic and most advanced questions and answers. This serves two purposes: First, it encourages people to read questions and answers they otherwise might not read. And second, it gives us all an opportunity to look over our old questions and answers and see if they require improvement.
I have a large number of questions and answers, so I've included five in each category, but if others want to post a smaller number, that's fine too.
EDIT: To clarify, what I meant by easy and hard is easy or hard for the typical reader to understand, i.e. basic and advanced.