I have a lot of different ways to start music class, see the post here about Musical Moments to Start Class, but one thing I really love to do is a "Song of the Month" (SOM) for each grade level.
I have found SOM also helps students to "change gears".
Opening songs set the stage for musical learning, provide a warm-up for the voice and the brain, and offer a predictable, structural transition to music class.
The song we sing may or may not be connected to the specific concepts or skills we are working on. An opening song is not the focus of the lesson and should not take up more than a few minutes. I see my students on a 4 day rotation, so 1 to 2 times a week depending on the week. You could certainly sing these for 6 to 8 weeks, depending on how frequently you see your students (and how sick of the song they or you get!).
Here are a few ideas for grades K-1:
I am not sure of the source, but it is a familiar tune to all of us music folks!
It is performed in a circle with partners facing each other and is a changing partner song/dance.
Hey, There, Friend
This is one I wrote late last week for my littles.
Grades 2 through 4
Bow Wow Wow
My 2nd graders love this song and dance. I love the giggles each time they turn around to find a new partner!
Third graders enjoy this song about chocolate! We often add a "B" section with composed rhythms created from, what else, chocolate! Kit Kat, Hersheys, Peanut butter cup!
Boom Snap Clap
Fourth graders love this as it sounds like "beat boxing"! They love the challenge of it and that there are "levels" of play. This is in my book, Hands to Hands, available here.
To Stop the Train
Another of my favorites! Love the way Rob Amchin processes this with movement first!