Here is a nice video on Fileteado Porteño, Argentina’s contribution to sign painting mostly produced in Buenos Aires. Here’s a whole Flickr album of Fileteado Porteño.

From Wikipedia:
Fileteado is a type of artistic drawing, with stylised lines and flowered, climbing plants typically used in Buenos Aires, Argentina. It is used to adorn all kind of beloved objects, signs, taxis, lorries and even the old Colectivos, Buenos Aires’ buses.

Filetes (the lines in Fileteado style) are usually full of colored ornaments and symmetries completed with poetic phrases, sayings and aphorisms, both humorous or roguish, emotional or philosophical. They have been part of the culture of the Porteños (inhabitants of Buenos Aires) since the beginnings of the 20th century.

The Filetes where born as simple ornaments, becoming an emblematical form of art for the city. Many of it’s iniciators where european inmigrants, who brought from Europe some elements or art, that where mixed with the local tradition, creating a very typical argentine style. The fileteado was recognized as an Art after the 1970, when it was exhibited for the first time.
[edit] Main formal features

In the book “Filete porteño”, by Alfredo Genovese, the anthropologist Norberto Cirio describes the main formal features from fileteado as:

A high degree of stylization
The preponderance of lively colours
The use of shading and highlighting to create the illusion of depth
The preferred use of a Gothic font style or highly detailed letters
The almost obsessive recurrence of symmetry
The framing of each composition when it is finished
The Efficient use of available space
The symbolic conceptualization of many of the images represented (the horseshoe as a symbol of good luck, the dragon as a symbol of strength).