Asmodian X and I have also been messing with the less powerful Linksys WUSB54GC adapters with varying success. Both seem to work quite well for wireless network monitoring, but when it comes to interception, the tools and kernel drivers available require a lot of work to get things functioning the way they should.
I'll also be showing off Sun's VirtualBox, which is an open-source virtualization hypervisor that seems to be flying under most peoples' radar.
Got something else cool and geeky to show off? It doesn't necessarily have to be security or even computer related. Let us know, and hope to see you this Friday!