Let us focus on the meaning or the etymological roots of apocalypse.
a. Apocalypse Abbr. Apoc. Bible The Book of Revelation.
b. Any of a number of anonymous Jewish or Christian texts from around the second century b.c. to the second century a.d. containing prophetic or symbolic visions, especially of the imminent destruction of the world and the salvation of the righteous.
2. Great or total devastation; doom: the apocalypse of nuclear war.
3. A prophetic disclosure; a revelation.
[Middle English Apocalipse, from Late Latin Apocalypsis, from Greek apokalupsis, revelation, Apocalypse, from apokaluptein, to uncover : apo-, apo- + kaluptein, to cover; see kel-1 in Indo-European roots.]
Therefore, let us focus on the original meaning revelation, rather than the colloquially derived implication of disaster.
The Mayan calendar can be seen as a revelation, promulgating the end of a major era for the Mayans. Just like, if people expect to truly live a biblical life-style, then we would need to observe the 50 year sabbatical Jubilee. This 50 year sabbatical calendar is indeed apocalyptic as it reveals the change in life cycles necessary to regenerate a community. Or, consider even the I-Ching cycles which are also revelatory on changes of life-cycles.
However, for those of us who would not accept the revelatory roles of cultural or religious calendars, we could use either the term myth or romance, instead.
The meanings of the words myth and romance are often limited by the people who use them.
Myth can be used to describe an account that is true but which involves events that are extremely out of proportion that the likelihood of those events taking place together is highly improbable.
I recall someone asking why the title of a certain Chinese classic was translated as "Romance of the Three Kingdoms", as sex and affection were the least of concerns in the story.
Perhaps, you could use either of these phrases too:
- The romance of the Mayan Calendar
- The myth of the Mayan Calendar