I am most recently out of preschool I'm willing to bet (born in 1987) and I stumbled upon this site while trying to prove the correct lyrics to my mother. The way I learned the song is as follows:

Today is Monday, Today is Monday,
Monday bread and butter,
All you hungry children,
Come and eat it up.

It continues on in that fashion with the final verse being:

Today is Sunday, Today is Sunday,
Sunday ice cream,
Saturday pizza,
Friday fish,
Thursday roast beef,
Wednesday soup,
Tuesday string beans,
Monday bread and butter,
All you hungry children,
Come and eat it up.