Possible Topics:

YouTube: Find videos to embed in your sites. Upload videos for training or flip teaching.

Reader: Organize your RSS feeds. (Remember that your announcements pages on sites creates an RSS feed)

Picassa: Photo storage - slide shows

Google Voice: Hide your phone numbers get a Google phone number. Texts and emails of calls and messages.

Google Earth: Explore the world, find information about items you find such as art in a museum you traveled to.

Google Sketchup
: Draw and create 3D renderings.  Can be used for student projects. web address shortener. Tracks clicks. Creates QR codes.