I believe that true Christianity is a spiritual kingdom. It is comprised of every nation, kindred, people, and tongue. There is no set language, national allegiance, culture, or calendar of holiday's in Christianity. As a result, Christianity is the most universally applicable religion on earth. As a result, Christianity can flourish in any setting and be lived and experienced among any devoted group of people.
The above being the case, this spiritual kingdom permeates all the nations and cultures of this world. And this means that Christians live in various cultures wherein the local culture has adopted festivals, traditions, customs, etc. Christians do well to abstain from participating in these cultural festivities especially if they involve/promote actual pagan practice or sinful debauchery. Halloween is one such holiday a Christian does well to avoid unless their participation only celebrates the season and the harvest. We do not celebrate ghosts, witches, demons, and the occult. A
Fall Family Night celebration or
Harvest Celebration is perfectly fine as a Christian alternative.
Many holidays such as Christmas, Valentine's Day, Saint Patrick's Day, Good Friday, Easter, and All Hallows Eve/All Saints Day/All Souls Day (Hallowmas), have their roots in the Catholic Liturgical calendar. These holidays were Catholic attempts to provide Christian set alternatives to the prevailing pagan festivals of pre-Christian Europe. And their attempts to provide Christian alternatives essentially worked as far as cultural identification is concerned. However, those pagans converted to Christianity often brought into these liturgical holidays traditions with pagan origins.
Today, many of these traditions are so far removed from their pagan origins that they have become more cultural/seasonal décor or tradition than actual "pagan practice". Christians can feel free to abstain from these festivals and all practices involved. Or a Christian can determine to what extent they will participate and even what elements of the "Christian tradition" they will recognize during each festival. It is a matter of conscience but care must be taken not to offend one's own conscience or the conscience of another.
Then there are secular or national holidays that are only related to our American identity:
New Year's Day
Martin Luther King Day
President's Day
Memorial Day
Independence Day
Labor Day
Columbus Day
Veterans Day
Thanksgiving Day
These holidays call to remembrance elements of our national identity. There are no overt religious meanings or origins for these holidays. A Christian may freely participate in any observance of these holidays at all levels unless conscience bids them otherwise.
Other holidays that are lesser known are largely "cultural" and have their emphasis in local history, local communities, or within specific ethnic groups. These are:
African Heritage & Health Week : February 1-7
April Fool's Day: April 1
Asian/Pacific American Heritage Month: May
Chinese New Year: winter, date varies
Cinco de Mayo: May 5
Father's Day: June, third Sunday
Flag Day: June 14
Groundhog Day: February 2
Kwanzaa: December 26 - January 1
Leif Erikson Day - October 9
Mardi Gras and Ash Wednesday late winter, date varies
Mother's Day: May; second Sunday
Native American Heritage Day - the day following Thanksgiving
Oktoberfest: late September to early October
Rosh Hashanah: depends on Hebrew calendar
Sadie Hawkins Day: Saturday that follows November 9
Yom Kippur: depends on Hebrew calendar
These cultural or ethnic holidays can be freely abstained from or participated in according to conscience unless participation will subject one to drunkenness or debauchery. Mardi Gras is a great example because of the revelry and public nudity typically associated with the holiday. Now, this doesn't mean that a Christian is in sin if they eat a Mardi Gras cupcake at a rather tame office party or carry in. But to attend a street event that is filled with excessive drinking, nudity, and revelry is nothing a Christian should participate in.
But it is important to remember, NONE of these holidays belong to the Kingdom of God. None of them. And so a Christian is in perfect harmony with the Spirit of God and Scripture if they abstain from all holidays and festivals altogether.