It may sound like a chore, and it will certainly take a substantial amount of work. But it's also a unique opportunity that can make a difference at decision time. Admissions committees put the most weight on your high school grades and your test scores . However, selective colleges receive applications from many worthy students with similar scores and grades—too many to admit. So they use your essay, along with your letters of recommendation and extracurricular activities , to find out what sets you apart from the other talented candidates.
This option is entirely new for 2017, and it's a wonderfully broad prompt. In essence, it's asking you to identify and discuss something that enthralls you. The question gives you an opportunity to identify something that kicks your brain into high gear, reflect on why it is so stimulating, and reveal your process for digging deeper into something that you are passionate about. Note that the central words here—"topic, idea, or concept"—all have rather academic connotations. While you may lose track of time when running or playing football, sports are probably not the best choice for this particular question.