The following is a great example of situational defense - and it's side-splittingly funny too. Who ever knew that traditional judo kata had a technique in which tori makes use of a frozen ham to defeat a knife-wielding attacker (at about 1:00 on the video)!
Reminds me of my introductory Japanese class in college in which one of the textbook examples was a customs person inspecting a traveller's suitcase and exclaiming, "What is this? A ham! That is not allowed!" We thought it was a pretty inane example but little did we know they were just protecting their national security!
UPDATE: BSM had a great idea! Click on the link below to purchase your very own self-defense ham. Send me an email and I'll verify that you purchased the ham and I'll send you the Official self-defense ham manual for free!