Static or pre-composed text to be sent via Twitter, Facebook, or email are some of the most simple Workflows that can be made and consist of two actions: text and one of the share actions. Consequently, I have posted below screen shots of my Workflows instead of doing a screencast.
When I make a presentation, I use Workflow to tweet out an invitation/announcement to attend my session about 30 minutes before my presentation. The workflow is an extremely simple one of a text action and then share with Twitter action (with the show compose sheet turned off). Only parts of the text changes for each presentation so it is essentially static text that does not change that is then passed to the Twitter share action.
I also use a static text Workflow to share links to my presentation materials that I can send out by tapping the icon on that specific Workflow icon on the home screen of my iPad or iPhone.
Workflow Links Pre-presentation