Choose a simple song, such as "Twinkle Twinkle Little Star," and make a recording of the song using a free audio software, such as Audacity by Sourceforge.net. Convert the recording to disc for easy use in the classroom.
Choose or write a calendar poem that contains the subject to be taught. For a simple song, choose a simple poem, such as "30 Days Has September."
Combine the poem with the song selection by matching the rhythm of the song with the rhythm of the poem. For example, substitute "30 days hath September, April June and November" for "Mary had a little lamb, little lamb, little lamb."
Write a song for "Twinkle Twinkle Little Star" using an opening line, such as "Twelve months in the whole year start with January, February and then March." Continue the song with lines such as "Next comes April, May and June. July and August follow soon." Create an ending with words such as "September, October, November, December are the last four months I have to remember."
Rehearse the song until you are comfortable with the lyrics and music. Rearrange the poem or music slightly to account for differences in timing.
Teach the students one verse at a time, repeating the verse until they memorize the words. Introduce the next verse and have the children memorize it before adding it with the first verse. Sing the calendar song at least three times during the day to reinforce the information.