For the Google I/O conference this year Google created a pretty cool Android App that included a number of features, including a schedule, details about the sessions, buzz about I/O via a real-time search stream and a conference map.
Google has now open-sourced the code for the app. If you want to create a similar app for a conference you can download the code and adapt it to suit your needs.
One of my favourite presentations from Google I/O this year was Map Your Business Inside Out by Brendan Kenny and Chris Broadfoot of Google. Essentially in the presentation Brendan and Chris demonstrated how the Google Maps API can be used to create indoor maps for large conference centers or shopping malls.
You can view the presentation in full in this video:
In the presentation Brendan and Chris explain how you can attach floor-plan overlays to a Google Map, how you can label the floor-plan and how you can develop custom Street Views for your map.
If you are interested in creating your own indoor map then you might find these resources useful: