From a sociological standpoint (in fact most social scientists will agree) rituals and rites preceeded the formation of what we would recognise as religion. For example, belief in spirits, congregating in a certain place, 'praying', group building exercises, war dances, face paints, insignia, totemism, blessing hollowed ground and burial of the dead has been observed in all cultures devoid of religion (in the sense of an overarching name applied to a set of principles and behaviour mechanisms) and belief in a God (from which rules and regulations are derived). See Pascal Boyers works as a starting point.
Most of the rites and rituals are socially constructed from within the social system. It is only when society became more complex, population grew that civillisations emerge (population of over 10,00 according to some anthropologists) do we see these rite and rituals codified into a common, unified practise and the emrgence of a 'God' and a 'God representative on Earth' i.e. king. The transition from flexible rites and rituals to a rigid set of rites and rituals emerged (who knows when) independently in Mesopotamia, Mesoamerica and ancient Egypt (who got there first?). It is a fascinating area of study.
But...and this relates to your OP Inzy...those who wish to say that atheism is like a religion are grasping at straws. There are several
types of religion:
1) Formal, instiutionalised religion e.g. Islam, Christianity. There is a clear hierarchy, claims of divine revelation, a Holy Book, a sacred place for pilgrimage, claims of miracles and they are either hostile to outsiders or they are world affirming. There are other criteria peculiar to this but a belief in the SUPERNATURAL is paramount.
2) Civil 'religion' (Steve Bruce explains...) society functions at times like a religion e.g. 'Americanism'. With sacred symbols of The Flag, The Declaration of Independence and that annoying U.S. patriotic song that begins with 'Oh say can you see...' The civil 'religion' is clutching at straws and has been criticised for this is not a new phenomenon. However, psotmodernists argue that traditional manifestation of 'religion' is moving towards this secular 'civil' religion type e.g. Christmas to 'Happy Winter Holidays'.
3) 'pick and mix society' or 'New Age mysticism' in which traditional boundaries have collapsed and people can pick and choose which ever ideology they like. Their 'saints' and 'books' are highly regarded but not sacrosanct. There are no punitive punishments for abandoning beliefs, there are no unquestionable authorities, no claims of divine inspiration are made and the rules, roles, rites and rituals are flexible.
Obciously certain sects are world rejecting and hostile to outsiders and may traipse on the boundary between 'religion' and 'ideological group/spiritual movement' e.g. Aum Shinrikyo or the Sai Baba cult.
In short, no, atheism is not a religion. It fails to meet even the basic criteria that one could construct for atheism as being a religion. Star Wars on the other hand, Jedi'ism, now there's a religion!
I hope sister that answers your question.
Topic: Atheist rituals