Hi Rob -
My children are 11 and 14 years old. I just finished watching "Hair Spray" with them. Great movie - not for your age kids though...
I use a walker outside of the house, am fairly mobile inside the house. Here are some things I do with my children: take short walks, watch them at their soccer games, pick them up from school (I can drive as long as it's not too icy or I'm not too tired), take them to a drive-in to get a milk-shake, cook with them, go out for a milk shake or hot dog. They also help me re-arrange the house to make it easier for me to get things done. Examples: yesterday we re-arranged the towel shelf in the bathroom, couple weeks ago we re-arranged the pots & pans in the cupboard: heaviest on top shelf, always have lids on top of pots & pans. My kids have made their school lunches since they were in first grade. They love it and it's always been a big help.
While I definitely try to live "in the present" I also want to prepare them to cope after I am gone. Part of my effort to do that is cooking with them each night. I figure that is fun for all of us, it helps me because I can't do it by myself, and it is teaching them how to cook. My husband used to be a chef, so our kids were cooking when they were your kids ages. Have them get out the bowls, pots and pans for you, tear up the lettuce, grate the cheese.
We also love to go swimming. Swimming is great for me and they love to go with me. I think options are limitless to what you can do with your kids. Play games, watch movies, short walks. It is an opportunity for our children to spend more time with us.
Best wishes