Is there a way to insert the current date and/or time in Google Slides?
Inserting field for current date/time in Google Slides
google presentations
UPDATE: Today Google announced that they will launch the Google Slides API, so very soon could be possible to insert the current date/time in a Google presentation.At this time Google Slides doesn't include a feature to insert fields to  automatically update dates, times or any other volatile information. To learn about what features are included in Google Slides take a look to Slides - Google Docs editors Help