The usual: Being spat on, insults, eggs, bottles, stones. Last week two kids were lurking by the side of the road, and one threw a stone at me - no hope of hitting me, as I was well aware of what they were up to before he even drew his arm back. Fortunately, about 100yds further up the road, there was a Police van waiting at the lights. I flagged him down and had a little chat with him about them, and he proceeded to go and give the little buggers a talking to. It may not have made any impression, but I must say I haven't seen them lurking since.
Otherwise, the only major incident was the airgun pellet in the leg a few years ago. Insults and the like pale into insignificance compared to that.