Here is another more "curricular" activity for large groups that is just dy-no-mite!
(pre-planning) Print the pdf attachment while you read this.
First you have to create (3x5 cards) groups of 4 musical individuals or items such as:
Non-pitched percussion: Snare Drum, Bass Drum, Cymbals, woodblock, and tom tom
pitched percussion: xylophone, marimba, timpani, piano, and bells
The Beatles: Ringo Starr, Paul McCartney, John Lennon, George Harrison
Woodwinds: Flute, Oboe, Clarinet, Bassoon, Alto Saxophone
Brass: Trumpet, Double French Horn, F Attachment Trombone, Euphonium, and Tuba (*stop calling them baritones')
American Composers: Leonard Bernstein, Aaron Copland, Stephen Foster, John Williams, and Scott Joplin
Famous Jazz Musicians: Charlie Parker, Duke Ellington, Thelonius Monk, John Coltrane, and Miles Davis
Famous Jazz Singers: Sarah Vaughn, Bessie Smith, Ella Fitzgerald, Lena Horne, and Billie Holiday
(remember, this has been done for you in the attached pdf that should be done printing now.)
however many more you need.................

then,

When students arrive hand them a card from the deck (make sure to shuffle) and tell them that they need to figure out which group they belong to and what the name of that group is. Give them a time limit and watch the processing begin. This will show you on the first day who your leaders are going to be and it is a blast to watch.

Lead the discussion and rational session with your new charges and praise them for really understanding music from a variety of ways. Print the attached PDF if you like for really a really fast turnaround. They are on Avery name cards if you happen to have those laying around, not necessary though. Regular paper or card stock works fine too.

Cheers!