GIS 4 Schools is developing new easy to use lessons that harness the power of ArcGIS Online. The first Five lessons are listed below. All lessons match Minnesota Social Studies standards. Future lessons are listed as well.
ESRI has updated ArcGIS Online Skillbuilder doc: http://esriurl.com/agoskillbuilder). This is a .pdf document that step-by-step moves you through working with ArcGIS to get you to a place of comfort with ArcGIS Online. Please check it out! I think you'll find it helpful. It could also be used with your students. Let them walk through it.
Also, ESRI had added additional Geoinquiry activities at http://arcg.is/rmueyClick Content to get to the actual Geoinquiry collections. Also, some of the geoinquiries are up for revamping and updating. If you've found any issues with them, please let me know. I'll pass that information on.
GIS 4 Schools provides lessons that educators can use in their classrooms.