We sang this in Collingswood Jr High chorus in maybe 1975, only we did it English "Oh be joyful, o be jubilant, put your sorrows far away Come rejoice and sing together this happy day."
gaudeamus hodie ; this is latin, the significance is "Let's rejoice today" - (please excuse my english, I'm french ! In french it is "Réjouissons-nous en ce jour"
We sing this too at our school and in our song it's super fast and we include words like Domino omnios and terra. I haven't heard anyone singing this.... Anyone else?