"Skipping" a 105 or 155mm howizter shell is one of the topics taught at the Comanchee County Cannon Cocker College (the U.S. Field Artillary School at Ft. Sill, OK).
In order to get an air burst (good against troops) when all you have is a delay (0.1 seconds) fuse, you can shoot at 'low angle' hitting an open flat area of earth, skipping the round into the air 'most' of the time - getting an air burst. I've never seen it done, just heard about it in class.