Tip of the day: app.BuildDate
You can try it with code like this:
MsgBox app.BuildDate.ShortDate+" "+app.BuildDate.ShortTime
The value does not change in the built application, so it works like a constant. And it's supported for Console, for Web and for Desktop. For more details, see Application.BuildDate. This also implements my feature request 2143 which can now be marked as resolved.