All of that is also great too, but I find it’s less of a waste to print a dozen of billboards at strategic locations vs. printing hundreds of thousands of newspapers and spam peoples mailboxes.
In Lausanne specifically, those billboards are also works of art in their own right so I do enjoy them.
How about in a free magazine which advertises all such events? Or a website that does similar? Also listings of "What's On" in more general media.