I have been working with the oomph tool kit and see how this can be a valuable tool. It can work well for corporate sites and areas where people need to share contact and events. It really does make the process of posting an event easy and allowing for a great way for people to add these events to their calendars (multiple types).
It also makes adding a contact to your contact list simple.
Take a look at these examples:
Contact Example: www.tilde32.com/contact.aspx
Event Example: Blog: http://jimiz.net/blog
The Oomph icon or microformat icon will show in the upper left of a site that contains microformat information.
There is a codeplex project for oomph: http://codeplex.com/oomph
Also some information on Mix Labs: http://visitmix.com/Lab/Oomph