Community service is for just an hour, after the morning meal. We call it karma yoga. You do and achieve things together. If you want to go fast go alone, if you want to go far, go together; an old African proverb.
Then there is the morning and evening get-together called satsang, and the afternoon sharing of knowledge, branded lecture, but more a workshop of interaction. Yes, there are mantras, prayers and chanting; and as Vishnudevananda came from a Vedic background, these are Vedic.