You're probably familiar with silk screening... it's been widely used for about a century now, so this isn't really a technology that's sneaking up on anyone.
Granted, things have come along a bit since the old days -- the inks are better, durability is waaay better and we no longer have to worry about the plague. Yeah, I have no idea what that last one has to do with decoration either...
Screen printing is THE best option for large batches of decoration. If you're looking to do 75+ shirts, shorts or wizard robes (like James did a few weeks ago for his Dungeons and Dragons club of Greater DC), you won't find a better, more economical method of doing so.
So, with that, the boss-man checks in one last time with a video on Silk Screening.