The most basic Vedic Yajnams (fire ceremonies) are Aupāsanam and Agnihotram. Aupāsanam is a daily household rite (grihya karma) which is offered together by husband and wife. Agnihotra is the basic daily ritual for the benefit of society (shrauta karma). Marriage is a prerequisite for these offerings. Traditionally, those who are not living a grihasta dharma (who are not married) perform Samida Dhanam instead of Agnihotra and Aupasnam. Both offerings are made twice daily, at the time of dawn and dusk into the sacred fire. As of 4/29/2015, we have uploaded an updated text for Agnihotra and Aupāsanam, which more or less adheres to the tradition of the Apastambha Suutra of the Krishna Yajurveda.
Agnihotra / Aupasanam Sanskrit
Agnihotra / Aupasana English