As most of you know, I've been a long-time fan of Slate. (Recently, its content seems to have taken a dive in hopes of attracting bottom-feeders, but that's another issue.) Slate runs a column, written by various contributers and interns, called Explainer. Explainer's writers researches a topic relevant to the news to give the reader the inside scoop on the subject. Explainer has answered question in the past like, "Can a doctor force you to undergo a procedure against your will?" and "How do you survive a 47-storey fall?"
Your weekend writing idea is to write and Explainer-like article. Those writing for the Explainer interview experts and do research - you'll probably just want to do research, since this is an article written on spec. However, concentrate on surprising questions that will garner even more interesting answers.
Maybe, instead of offering suggestions for questions that I don't know the answers to, I'll open up discussion to you. What's a burning question you have that you'd like someone else to research and answer? Feel free to discuss here or in the forum - whatever's easiest and most conducive to interaction. For inspiration, click on the link to Explainer above - you'll see just how creative you can be, and you might get some ideas for other articles while you're at it.