Its Japanese for "chit chat" and a structure to keep people from blabbing on for too long with a powerpoint or similar. 20 images each lasting 20 seconds (automatically changing over) with students or colleagues speaking live to images or doing a VO (voice over) in podcast format.
Pechakucha.org has a range of examples. Here is a snippet from one example...
hyphen31 (Don Collins) has been playing with technology since the days of the Apple+. On the web well before www, he continues to savour the richness of the webiverse in small bytes. He finally leapt from the couch and created this own domain & website forsaking all earlier incarnations...