A coworker stopped me the other day and asked for suggestions on her early 19th century German immigrant ancestor. I began listing suggestions and asking her questions about what she knew. As soon as I got back to my office, I had three ideas for my own "brick wall" person I had put aside some time ago.
Sometimes just talking to someone else about their research problem or giving them some help gets you to thinking about your own problem. And, you've helped someone else with their research along the way as well.