This is a really great series of videos on different ancient and medieval weapons and equipment that I learned about at Tenkar's Tavern. The videos cover details on the proper way to handle different weapons and their effectiveness in different situations, the use of shields, the utility and design of different types of armor, even torches and water bottles. The information is perfect for running games; lots of ideas for combat stunts for players and hazards for game masters.
Here are some samples:
Argumentation and Representation in the Internet Age
58 minutes ago