My general advice is that college applicants should do what they are passionate about. The student who has a superficial smattering of extracurriculars but no depth or leadership experience will impress no one. Put yourself in the shoes of the admissions counselor -- the college wants to matriculate students who will bring passion and talent to the campus community.
Students should also think broadly about how an extracurricular activity can be defined. This article discusses how Rubik's Cube can be transformed into an excellent extracurricular activity. In response to that article, Sarah wrote in and described how she turned her love of finding free things into an extracurricular activity:
"After reading this article, it made me think of my 'passion' of hunting for free things on the internet. I've done it on and off since I was ten, and I've had some minor successes. I got lots of toiletries, boxes and textbooks and novels, and free food. I've donated them to several charitable causes throughout the years, and at the beginning of this year, I consulted with one of the vice-principals at my school regarding creating a Freebie Club in which people would collect items based upon a monthly theme (ie, animals) and donate the collected goods to a chosen charity at the end of the month. She said it sounded solid, but that the school didn't want to pay overtime for a teacher to advise it, which is required at my school, and suggested that I join a club that had a similar goal. I did that, and presented a plan, which involves a charity I already volunteer at, to the club leader. She said it sounds good."
Sarah's activity will look good on a college application for several reasons: it's unusual, it helps people, and it demonstrates Sarah's creativity and initiative.
The competitiveness of college admissions has many students engaging in activities that they don't really enjoy simply because they think they need to in order to get into college. Sarah's approach will be more fulfilling and less likely to lead to burn out. Identify your true passions, and then figure out a creative way to transform them into an extracurricular activity.