My mum will pick up the kids from school if I cant and bring them back to mine if its easier, feed them while shes got them...she does this 2/3 time a month.
She will also have them overnight if I warn her 3 weeks in advance she does this 2/3 times a year....although she did say last time she only wants one at a time as they wont sleep but I think thats because shes putting them to bed too early.
She will cancel things to look after them at the drop of a hat...
How often do your parents help out, pick up, look after your kids?