date - Get the Date part of  a DateTime
dateTimeAdd - Add a duration from a DateTime. If no units are supplied, then minutes will be assumed.

dateTimeSub - Substract a duration from a DateTime. If no units are supplied, then minutes will be assumed.

dateToNumber - Convert a date to a number
dateToString - Convert a portion of a date to a string
dtToDtAdd - Add one dateTime to another -- returns duration (always minutes or seconds).
dtToDtSub - Subtract one dateTime from another -- returns duration (always minutes or seconds).
now - Get the current DateTime for this server
siteDateTime - Get the current dateTime for the site associated with the target
time - Get the Time part of a DateTime
timeToMinutes - Convert a Time to minutes
timeToTimeAdd - Add one time to another -- returns duration (always minutes).
timeToTimeSub - Sub one time to another -- returns duration (always minutes).