I find this website pretty helpful: http://www.healthstatus.com/cbc.html
Just enter the time you spend on each activity (and your weight), and you'll get an approximation of calories burned.
I also have core secrets with Gunnar!
I consider that part of my weight training. I don't really count that workout in my daily calorie totals, and usually just count my cardio time in the gym. I make a note of when I use the ball and count that as wiggle room for the day. I figure it's around a hundred calories or so. I do the same thing for when I walk home from work (25 minutes) and it makes me feel better if I slip up and eat a little too much one day.