Many atheists stop following the traditional, religious holidays observed by religious people and theists. Others still observe them, but they have lost their former meaning. Some atheists have tried to create new, secular holidays as replacements - like Solstice and Darwin Day. Is this a good idea?
There can be a lot of social value in holidays, whatever ostensible reasons one has for celebrating them. Holidays can serve to form a connection to your own past by evoking memories of past celebration. Holidays can form and reinforce connections with the friends and family with whom you celebrate. Holiday events can also create connections across an entire society as people develop parallel experiences which forge subtle bonds.
Rituals that are integral to holidays can be important because they are often significant means of social communication. Ritual is a type of behavior which "says things" rather than "does things." Sometimes what is said can be negative, for example rituals which serve to reinforce a person's status as someone subordinate when they should really be equal. Often, however, what is said can be quite positive because it lets others know that you continue to care about them.
This means that the rituals in holidays can be necessary means by which relationships with others are reinforced or even furthered -- and in ways which may not be possible in quotidian contexts. I'm not sure, though, if any of this is enough of a reason to create new holidays on completely secular foundations and for completely secular reasons. What do you think?