Quick Look: Quick Look: What's Trending says it features stories that are currently popular or have recently peaked people's interest on the internet. I'm not sure how relevant the stories currently are, though - on March 17th and there are videos pertain to Halloween, The Superbowl, Charlie Sheen's HIV admission, and Thanksgiving. Those stories are all well past their prime.
The "current trending" videos are not categorized. There is a search option but you will need to be very specific with your subject matter or you will not get any results.
A sample video from the What's Trending YouTube channel can be viewed below.
-- Information is current as of March 17, 2016
Developer's Channel Description: What's Trending serves as a 24/7 news hub, covering and curating the most viral and shareable content across the social web.
CHANNEL STORE CATEGORY: Web Video
CLOSED CAPTION ENABLED: No