Keep a list of things you want to understand someday. It turns boredom into a menu.

Boredom is usually a shortage of candidates rather than a shortage of interest. With nothing queued, an idle hour goes to whatever is nearest, while a written list of things you have wondered about gives that hour somewhere to go. Writing them down also catches curiosity at the moment it appears, which is when it is strongest and easiest to lose.

Start the list tonight with three things you have genuinely wondered about, and add to it whenever something strikes you. When you are at a loose end, take one off the top. Nothing on it has to be useful.