You might find this hard to believe, but here goes: Sometimes I'm the last person to know about something trendy.

This often becomes clear during the school year when the students start doing something that I think is clever, and naively I think they invented it, only to discover too late that it's the coolest thing going.

Or at least, it was the coolest thing at the time.

Such was the case when I stumbled across this week's New Thing for Music Monday on Sunday night.

I was in New York for the 4th weekend, and I didn't experience any new music, so Sunday I went searching through some sites for something new.

After a quick glance through what's been hot on iTunes I popped over to YouTube and clicked 'music'. One of the first videos to pop up there was Anna Kendrick's "Cups", which I guess is also known as "When I'm Gone" from the movie Pitch Perfect.

I had heard this song recently on the radio, and I feel like I had heard of Anna Kendrick. She's an actress, but I just looked at her IMDB page and I have no idea if I've ever seen her in anything. Maybe I'm confusing her with the baseball player Kyle Kendrick. Or Anna Friel or Anna Faris. Anyway.

So the song's catchy, but then she starts doing this thing with the cups and clapping in the video, which the fifth graders spent most of last year doing. I thought it was something they had learned in music class. Turns out, it's from a movie.

So that's this week's new music. Hopefully I just helped you avoid doing something embarrassing by introducing you to this corner of popular culture. Maybe I should go see Pitch Perfect and write it off as a business expense.

Here's the video with the aforementioned cups performance:

Well look at this. Apparently she learned it by watching someone else. Wonder if the kids knew that.