Modules to cover in a 1-2 hour slot entirely depend on your audience’s interest or focus. What other classes are they taking? What are they prepared to make use of immediately?
Be sure to mention math, decimal and datetime and time and re.
For IT-types who will be doing file-oriented work: glob, fnmatch, os, os.path, tempfile, and shutil.
Database folks must hear about sqlite and json.
Simulation audience may want to hear about random.
Web developers must hear about urllib2 from a client point of view. Also Beautiful Soup and an XML parser of your choice.
Web developers must hear about logging and wsgiref from a server point of view.