Are you working full-time BarefootDancer? I'm working full-time now, but before I was I went in and volunteered to help in school one afternoon a week (in another class). This gave me an insight into 'school life', and helped me to ask the kind of specific questions that would elicit responses from the boys. Is that a possibility for you?
General advice; rather than asking "What did you do at school today?" try phrasing specific questions:
Did you have an assembly this morning? What happened in assembly? What did the HT talk about?
What did you do in literacy today? Did you do writing or reading? What did you write about? Did you enjoy it? Did you find it easy or difficult? Did you manage to finish the work in time?
Crikey, that sounds like the Spanish Inquisition - it isn't like that, honestly. It's just about teasing out information, showing your dc that you're interested in what they've done.
Personally I tend not to be too focused on their 'academic learning', but rather on the social side, whether they're happy and having fun, and whether they're behaving well.
The other key thing of course is to engineer a time for such chatting: if a chat with you has to compete against watching the TV or playing on the computer, then they're bound to be reluctant. Walking home from school worked very well for us. Or you could all sit down around the table for a drink and snack after school. For some people sitting down and having a cosy chat about the day just before bed works well. Or you could take her out for a special treat at the weekend to a 'grown-up' coffee shop to talk about her week at school ..
HTH