PowerShell module for creating calculated variables in PowerShell
> # import the module into your session
> import-module autovars
> # define an automatic variable
> new-autovariable -name now -getter { get-date }
> # use the automatic variable
> $now
Wednesday, May 07, 2014 12:10:11 AM
> $now
Wednesday, May 07, 2014 12:10:14 AM