Use Gmer to detect the Hacker Defender rootkit
Try out Secunia Personal Software Inspector
Try out File Shredder
Use Helix to steal deleted data from RAM and HD
Compare speed and security of 802.11g and 802.11n (I have both available to use)
Set up TrueCrypt drive encryption and demonstrate it
Get BIOS and/or BitLocker passwords from RAM location 041e with a hex ram viewer
Test DeCrapifier - one guy said it ruined his MS Office
Test more rootkits, there are a ton here: http://www.rootkit.com/index.php
Hack into a fingerprint reader (I have one you can use)
Install Tripwire and detect an intrusion (http://www.techradar.com/news/computing/how-to-catch-linux-system-intruders-467913)
Set up software IP Phones (http://www.3cx.com/VOIP/voip-phone.html) and capture traffic with a packet sniffer
Set up an Asterix open-source PBX and connect software IP Phones to it, sniff the traffic
Download the Perspectives Anti-MITM Firefox Extension and see how it works, try a MITM attack with it on.
Download the Free 'Trojan-Proof' Password Tool and test it out.
Try the XArp ARP spoofing detection tool and test it at detecting a real ARP attack, such as with Cain
Python 3.0 is out. It has a lot of changes. Try it out--write some simple code and show it to the class.
Test ReadNotify--a service that tracks emails you send. Can you prevent it from working with firewalls, or Noscript, or by reading your email in text-only?
Try some of these awesome router hacks-- you should be able to turn off router security, change the administrator password, etc.
Make a Bootable USB Flash Thumb Drive to Install Vista with.
Try the LocatePC system to track stolen computers. How does it compare to Adeona?