I know it can sometimes be a drag if children are very inquisitive, or indeed having to explain things out of necessity, but is there anything you enjoy explaining to them (your own DCs, or someone else's)?
I like telling my inquisitive nieces (aged 4 and 6) about netball, although they're too little to play it yet; teaching them to play simple tunes on the piano; and I love telling them about old technology, such as records and video cassettes.