A repeating song in French. It is roughly equivalent to 99 Bottles of Beer on Wall in English, only it counts up instead of down, so it can go on forever (see: the song that doesn't end. The words go like this:

Un kilomètre à pieds, ça use ça use,
Un kilomètre à pieds, ça use les souliers
Deux kilomètres à pieds, ça use ça use,
Deux kilomètres à pieds, ça use les souliers
Trois kilomètres à pieds...

And so on, counting up as high as you can go, or until you reach your destination. The translation into English doesn't sound quite as fluid, but it is basically this:

One kilometer on foot, it wears out it wears out,
One kilometer on foot, it wears out your shoes.
Two kilometers on foot, it wears out it wears out,
Two kilometers on foot, it wears out your shoes.
Three kilometers on foot...

It's also fun when you get up to numbers like 98, which in French is "quatre-vingt-dix-huit", which needless to say has more syllables than "un" or "deux". I'm not entirely sure of the history of the song, but my guess is that it was, obviously, some sort of marching song, perhaps of military origin. Today it's pretty much held in the same regard as the aforementioned 99 Bottles of Beer on Wall, a silly song to sing when you're bored and travelling.