For quite a number of years now, Japan has had a form of advertising that I found quite interesting - the huge advertising trucks that drive around in highly populated areas such as Shibuya, Shinjuku, Ginza and so on. In Japanese these are known as "Koukoku Torakku" 広告トラック] or literally "advertising truck"
Done a Google to check up the prices to discover that they cost more than I thought. For the ad in this photo which looks roughly like a 9.4 x 2.6 meter space - this will cost 2600000 yen (about 22000 USD at todays rate) for a week which includes production and blasting out of music as the truck drives around (with driver included). Prices are available on this site if you are interested ^^
I've never seen this form of advertising in any other country but do admit that it does catch my eye. Anything like this in your neck of the woods?