Amateur, need help finding right plugin

I’ve got some info that I need to add to a new page, but it’s fairly repetitive. I’d like to add a way to “hide” the description under the category it goes with until the customer clicks on it, like this FAQ page does:
http://travel.state.gov/passport/faq/faq_1741.html

I don’t know what plug-in to use to make this happen though. I don’t want my customers to navigate to a different page, I want them to stay on the same page like the above website does.

HELP!