Throwing eggs

A (kind of) "funny" Irish game is Throwing Eggs on people walking in the street in the evening from a car... Weird game, isn't it ? The first time I saw this game, I was walking down the street with friends, and suddently a car passed by and threw eggs at us! What the f*** is that??? I thought it was young drunk people having fun... After living for several months in Ireland, I can say now, it can happen at anytime and it's a random game appreciated by Irish...