The Dapper Dans barbershop quartet has been charming audiences with old-timey tunes since they debuted at Disneyland in 1959. In honor of National Barbershop Quartet Day, check out a few of their most melodious moments—including barbershop twists on some familiar songs.

1. THE DISNEY MEDLEY

A typical Dapper Dans number? The Disney Medley, a set performed year-round, which includes songs like "Zip-a-Dee-Doo-Dah" and "When You Wish Upon A Star."

2. THE BOY BAND MEDLEY

For a 2013 special event called "Limited Time Magic," the Dans threw a selection of boy band hits into their mix. Songs from The Backstreet Boys, 'NSYNC, and One Direction all made the cut.

3. THE 'CADAVER DANS' HALLOWEEN MEDLEY

Every year, a few Disney parks host a special event called "Mickey's Not-So-Scary Halloween Party." The Cadaver Dans (the group's Hallow's Eve moniker) are exclusive to these parties, where they perform live renditions of songs from The Nightmare Before Christmas (1993) and other haunted tunes.

4. THE CHRISTMAS CAROL MEDLEY

Similarly, the holiday season brings "Mickey's Very Merry Christmas Party" to the amusement parks. There, you'll find the Dans caroling in their holiday finest.

5. THE 'BAROQUE HOEDOWN' SONG FROM THE MAIN STREET ELECTRICAL PARADE

The Dapper Dans are multi-talented. In addition to singing, they also play Deacon Organ Chimes, perhaps most impressively in this rendition of the iconic Main Street Electrical Parade theme.

6. THE TIME THEY CHANNELED FROZEN'S ELSA

When Southwest Airlines opened a new nonstop route from Dallas's Love Field airport to Orlando in 2014, the Dans showed up to help passengers celebrate.

7. WHEN THEY HELPED WITH A WEDDING PROPOSAL

This bride-to-be thought she and her boyfriend had simply volunteered for an audience participation portion of the Dapper Dans set. What she didn't know was that her boyfriend had talked to the Dans before the performance to arrange for something a little more.

8. WHEN THEY SHOWED US HOW TO RIDE A BICYCLE BUILT FOR FOUR

The Disneyland quartet can often be found cruising around Main Street on a custom Schwinn bicycle built for four. Here's how they manage to accomplish that challenging task: