With the combined success of The Sing-Off and Pitch Perfect's "Cups" from Anna Kendrick becoming an unlikely radio hit, a cappella has officially hit the mainstream. And with groups racing up the Billboard charts, touring the country and linking up with superstars, the fever shows no signs of subsiding. 

As Fuse News researched earlier this year, the scene is experiencing a massive surge in "a cappopularity," mainly thanks to groups uploading and sharing on YouTube. While there's certainly a whole lot to sift through, we've selected seven acts to check out right now. 

Get lost in a cappalooza of a cappella now!

Remember the first time you watched a One Direction video and you instantly fell in love with the adorable, well-groomed, talented lads singing? That's sorta what happens when you watch James Madison University's Exit 245, a 14-member all-male group. The Virginia-based act deliver cinematic music videos spliced with shots of these all-American boys.

Watch their emotionally jarring rendition of David Guetta's "Titanium" above or their adorable, bass-y cover of Mariah Carey's "All I Want For Christmas Is You" below.

Chicago-based Gentleman's Rule seem poised to be a cappella's new sensation: These dudes had a special air on PBS last month, performed with country superstar Jake Owen and have gone on nationwide tours. 

Plus, mashups don't get more brilliant than Pachelbel's Canon mixed with Nelly's "Ride Wit Me." Watch more here.

Repping the ladies, we have the Noteworthy from BYU. Noteworthy bring precise harmonies and a subtle, smooth style. Just watch their mashup of David Guetta's "Without You" and Mumford & Sons' "I Will Wait" that evolves into an almost glitch-pop styled production. Whoever gives female a cappella a hard time needs to watch these girls. Check out more here.

All-male a cappella group Academical Village People call University of Virginia home and sing all types of genres that span the decades. Besides listening to their self-created arrangements, we love watching the group's hilarious uploads. Listen above to hear them reimagine Hoobastank's "The Reason" as an explanation for being a bad boyfriend. 

Plus, audiences really like them. Watch how hyped the crowd gets for their live performance of Owl City's "Fireflies"—kicked off with a flashflight light show—and just try not to get caught up in their energy. Watch more here.

To kick off your YouTube a cappella education, we'll start easy with the biggest name in the game right now: Pentatonix. The quintet won the third season of NBC's a cappella group singing competition The Sing-Off and now boast 5.5 million subscribers on YouTube. While already revered in the a cappella scene, this Christmas season gave PTX their mainstream break when their rendition of "Little Drummer Boy" (below) went viral, snagging 32 million views and racing to No. 13 on the Billboard Hot 100. 

In case you doubt the power of a Pentatonix cover, every one of their covers on YouTube has more than one million views, including recent hits by Pharrell (above), Christina Aguilera and more. Watch 'em all here.

It's been a little more than six months since their first YouTube upload, but Chris Etscheid, David Marenberg and Kris Fitzgerald—aka KINGS ROAD—are a cacuties to keep your eye on. They describe their sound as doing everything from "crunchy-chord ballads to EDM." 

While we are hardcore-digging their Calvin Harris/Emeli Sande/Timeflies mashup "I Choose Love" (above), we're obsessed with its adorable accompanying music video chock-full of cute boy-meets-boy encounters.

Watch a mashup of  The Wanted, Ellie Gouldin and OneRepublic below—with another cute visual—and more videos here.

Mike Tompkins isn't necessarily an a cappella group, but he might as well be. The dude rose to YouTube fame with his incredible one-man covers where he plays every instrument with his body. With 1.2 million YouTube subscribers, he's teamed up with stars like Bonnie McKee (below), Karmin, the Pitch Perfect cast (above) and performed on Today and The Ellen DeGeneres Show. 

In case you haven't seen him on your computer or TV screen yet, watch here or check out more videos here.

NEXT: 10 Unexpectedly (And Unexpectedly Amazing) A Cappella Covers