When did my student access the course last?

If you click on [classlist] in the upper navigation bar, you can view the date and time a student last accessed the course. Students cannot see this, only instructors and TAs.

Previously, this information was only available through the User Progress tool.

"User progress" can be used to view whether or not a student has accessed a particular piece of content, quiz, survey, etc. More can be found at:
http://d2ltipsandtricks.blogspot.com/2009/04/using-user-progress.html