I used to sail Lake Garda (where the video was shot) every other weekend during Summer many years back when I still lived in Germany.
The jumping the boat wake thingy started back in the early 90s. There used to be a big tourist boat with a massive wake going up and down the lake. It was funny to watch... a bit like what you see in the youTube video... as soon as the boat would show up dozens of people would be racing towards the back end of the boat to throw them selves over the wake.
BTW, in a northerly wind lake Garda can produce some solid 6 foot wind waves. They get even bigger when you get one of those very rare southerly storms combined with a Thunderstorm over the mountains. There is a picture in one of the windsurf shops where a wave pretty much engulfs a small gate keepers house at the entrance to Torbole harbor.
The consistent winds, warm weather and great nightlife as well as the close proximity to Munich and Austria make this a very popular place for many wave sailors during summer that crave for some wind but can't get away to portugal or the Canary Islands due to work commitments.
