How can you add DateTime and Boolean values into cells?

[metkhoo]

Seems like numbers and strings are OK but how do I add values to cells where the cell datatype is boolean or date/time?
For date/time I expect I need to create a decimal to represent the date/time value where 1/1/1900 is 0 and add that to the cell - but then how do I format it as Date/Time afterwards?

And what about a Boolean TRUE or FALSE ??

Thanks in advance