I have fond memories of playing conkers in primary school. Sometimes you got a rapped knuckle but children's sports is full of cuts and grazes, and it didn't hurt as much as slaps anyway. The main issue was that some kids would inevitably harden their conkers by putting them in the oven or lacquering them, and so on. But spotting that was part of the charm.
Being of a geeky bent, I tried them all. It never worked. They go brittle and shatter, or they go soft and fall apart.
(When I was a kid, conkers were so prized we chucked sticks at them to try to get them to drop. So it was a bit of a shock to me when they started just being left where they fell. Kids today, off my lawn, uphill both ways, etc etc).
