One thing that the children (visiting and my own) did was sow some carrot seeds.
Last year we grew a variety of especially short, fat carrots but this year we are having a go at growing multicoloured “heritage” carrots. I have no idea whether they will work – we’d had the seeds over a year so I hope they weren’t off.
One advantage of growing vegetables is that it encourages children to actually eat what they’ve grown. At the moment, my children are a bit wary of stuff that looks even slightly different from what they’re used to so perhaps this will cure that a bit. If they work.