Kajo is a TV personality. This is a quite of an understatement; Kajo has made tons of really, really, really funny stuff, and has an original sense of humor, which makes him even more remarkable.
He used to run a TV program called Kettunen, in which he told funny stories about his observations and little riddles of life, and, simply put, gave something to think of - if not something serious, then something less serious. These writings, and then some, have been published as three books.
Other TV series of his that I need to mention are Naurun Paikka (q.v.), Kajon Musiikkiohjelma, in which he introduced us to some interesting sides of music, and the most recent one, Ihmisen Käsikirja (translates roughly to "Human Being: The Handbook").
Some say that the funniness level of his stuff has gone to decline; I can only partly agree. While Ihmisen Käsikirja wasn't as high in fun-per-minute scale as his previous works, the content was still pretty much, hm, Kajoesque.