Bisexual is a term originating from the Greek word Bi, meaning "Two, Three or Good Morning", and the Latin word sexual meaning "sexual or six digits". Bisexuals are people who have become obsessive fans of the television series Good Morning, America, seeing as bisexuals are often confused by the concept of digits and consider seven to be six or six to be nine.
In most civilised societies apart from North America, bisexual means "one who wants to ride a bicycle". This is also the most common way of referring to a person who rides a bicycle frequently - a bisexual. This is also where the term town bicycle came from.
In other cultures, namely geek culture, bisexual means "has had sex, twice".
There are several types of bisexual, including bisexual men, bisexual women, and bisexual opponents of binary conceptions of gender. There are also militant bisexuals a.k.a. the Blue Berets, religious bisexuals such as the Pope Benedict XVI (who are very much homo - as in homosexual - but not any sexual) and rainforest bisexuals such as featured in the film King Arthur (who paint their faces in the colours of the rainbow and then ride bicycles).
While homosexual marriages have been sanctioned in some places, Bisexual marriages are still rare. This is partly due to the fact that at least 3 partners would have to be involved in the marriage, rendering one aspect of the marriage to be Heterosexual.