My best memory is taking all my mom's blankets, garden chairs, any light enough to move chairs, etc, outside on the grass, and building a "house" with tunnels, rooms, etc and having a picnic in there for the day.
It was brilliant, and for some odd reason she never complained or even mentioned the time it must have taken her to get all the grass bits out again! 
Also baking together, getting everything covered in chocolate batter, including our faces and most of the kitchen. It never even occurred to me that we might be creating extra work for her - it was just exciting and fun, and she made us feel like we were ever so creative.
I grew up thinking that there were no limits to what you could achieve, as long as you chose what you find interesting, not what others expect you to.
So in short, even though we had strict rules on certain things (bed time, eating veg, school work, language, respect etc), we had the freedom to just "be". We very, very rarely did any organised activities, but I remember painting at my mom's feet whilst she worked on the sewing machine, reading, puzzles, just knowing my mom was there. I think it was great for encouraging creativity.
I wish I could be more like her - I think I try to plan too much and get stressed about the small things.