You can also dynamically change the name of your report and use date and time in the title, then your end user would not even have to open the report to get the information. The preview below shows you how it would appear.
I agree with Stephen that you could easily add a formula and drag that to your report.
I often use this trick during development so that each time I create a report I get the latest iteration. If you don't do this, the report will just overwrite the previous version with the same name.