"Foley Art" is so named due to its creator - a certain Jack Foley. Jack was a radio man called into Universal Studios at the end of the silent era when the Warner's new sound sensation The Jazz Singer was proving a wild success. This was 1927 and Jack and his team were assigned to create the sounds for Universal's big picture Show Boat that now must be made a "sound film." Microphones of the day could only pick up dialogue, so all additional sound had to be created in post-production. This task required deft hands as it was all done in real time - the movie would be projected on a screen, recording was started and Jack and his team would create the sound as the movie played on the screen - being careful to synchronize footsteps, gunshots etc. with what was happening in front of them.
Like all film techniques, technology has significantly changed the game, but to me foley art will always have a simple charm. Just try the clip below and see if you aren't interested.