If you just happened to wander onto this page, I'll fill you in on what these folks are doing.
Have you ever played Dungeons and Dragons?
Enjoyed fantasy movies such as Excalibur, Braveheart, DragonSlayer, Legend, Etc.?
Well, there are 2 types of organizations that can let you experience the excitement of medieval battles.
One is the SCA (Society for Creative Anachronism).
They hold full contact battles with full armor.
They require a bit more of a financial commitment to purchase armor and weapons.
The other type of event is a LARPG (Live Action Role Playing Game).
These events use padded weapons, so full armor is certainly encouraged, but not required.
Some events are small, with 20-30 people, whereas some SCA events can have up to 2000 people participating.
Some people "role-play", or take on the mannerisms of a character, and speak in historical language styles,
but many people do not. It is really up to one's individual preferences. One could sit at the pub all day, or fight in battles
for hours at a time. LARPG's usually run 24 hours a day, so night battles are possible as well.
Regardless, I can attest to the fact that it's a lot of fun!

Anything's Possible: Padded Weapons and Armor
Mythical Journeys: A well done LARPG, with a nice webpage and lots of images.
Lione LARPG: another popular new england LARPG .
International Fantasy Gaming Society (IFGS): International LARP Organization
LARP.com's Links: Tons of Links To LARP Sites
Maspien Armours: Armor, Weapons, etc.

There are many other suppliers of armor and weapons, but these are some of the better sources.