One concept that is key to The Montessori approach to educating children is that the work of learning is enjoyable. It is enjoyable enough that children will choose to work in the same way they might choose to play. Even though I know this fundamental idea it still surprises me sometimes when my kids choose to do "homework"!
We have activity shelves set up and the kids each have a skills workbook to work on when they like. We try to do a page or two every couple of days but often once they get started they enjoy it so much they do 5-10 pages.
We also have some other workbooks - like cutting exercises - which they greatly enjoy. My enjoyment depends on the activity. Mega's cutting activities often make me nervous as she tries hard but her ability hasn't caught up yet!
Mega and Zilla are also easily inspired to create their own things. The recent art "boom" has been making books. Zilla created a very nice zoo book with drawings of various animals we saw on a recent visit. Mega's drawing skills still need to develop a bit to match the images in her mind but since her speaking/signing is pretty understandable she'll often as someone else to draw the things she is imagining :-)
Mega's body art in the first couple pictures is also a result of a recent artistic "inspiration" which struck while I was in a different room... Normally I can redirect the artistic moods into something a bit more constructive!