While Get-Date returns the current date and time, it really returns a DateTime object. You can use this object to find out more about the date or to calculate date and time offsets as it has a number of very useful properties and methods.
$date = Get-Date
For example, to find out if Daylight Savings Time is in effect:
$date.IsDaylightSavingTime()
Or, try adding 10 days from today:
$date.AddDays(10)
Next, go back 5 days:
$date.AddDays(-5)
Hint: Use PowerShellPlus to get automatic code completion. Once you type the ".", you will see all the properties and methods an object exposes.