That clip is the winning entry from the March 2003 edition of the programme. The programme is aired twice a year and has been going since 1979. It's a huge favourite in Japan, but is barely known outside the country, except amongst a few fans who hunt down poor quality clips on the internet.
Each act is voted on by a panel of judges and a score of fifteen or over wins a medal (presented by a bunny girl - for reasons beyond my comprehension). The overall winner of each show gets... well, I don't know what exactly, but they must get something. Some acts are very simple indeed, whilst others involve a huge amount of effort, but they're all rather imaginative and surprisingly inventive. Sometimes there's an act that I simply have no idea what they're doing, but for the most part the fun comes from realising just what it is they're up to. Having some cute kids as part of the mix is usually a good way to get extra points. Heck, even one of the judges is a child.
Occasionally, there are celebrity entrants (most famously Morning Musume and this year a certain K-pop group), but the contestants are mostly ordinary people which is one of the reasons I like this so much. It's not about some talent for singing with which someone's been randomly born, but about the imagination of normal people - anyone can take part and enjoy success with even a simple idea if it's clever enough or capture's the judge's imagination too.
Most contestants are a part of a team and the most common technique is that of the kuroko from Kabuki or Bunraku theatre. The kuroko (黒子) are stagehands who dress in black (sometimes blue or white) against a dark background in order to be invisible when manipulating stage props. In actual fact they often appear in front of backgrounds that aren't dark, but the convention is that the audience regard them as invisible. Oddly enough, in most Japanese theatre (especially bunraku) ninja characters are usually portrayed as invisible and employ the kuroko outfits accordingly and it's been suggested that this has led to the convention of ninja being shown wearing black outfits. Real ninja might have worn black outfits occasionally, but it was far from commonplace. See? This blog's educational too.
Thanks to the dedication of one chap, there's now a YouTube channel where most of the show's clips can be seen in decent quality. Go there and subscribe. Here are some of the entries from the latest show.