One of my favorite things to do for my Mom, and one that my Mom really enjoys when I'm able to do it for her, is to plant her container garden.
She has a lot of gorgeous pots on her back porch. We try to add a perminant plant every year, like lavender, but the rest I plant in anual bedding plants. She then has gorgeous flowers to enjoy all spring, summer, and most of fall.
It might be fun for the both of you to take a class together. If you're really into environment, or animal type sponserships, take a stain glass class together. Create a lovely window, and donate it to charity of your choice. Our local humane society has a thrift store. Other groups have yearly auctions. A stain glass would be a welcome item and would probably sell very well. Best of all, you'd get to learn a cool new skill, and spend time with your Mom.
~Garnet
Oh yeah! You can take a large leaf, like a rubarb leaf, and make a cement cast of it, which can be set out for the birds(on a pedistal) to have a birdbath, or you can put them directly on the ground and provide shelter for frogs, toads, garter snakes, and salamanders.
Link for you:
http://www.blossomswap.com/cast-concrete-leaves.html
Another thing that just popped into my brain! Does your Mom garden? If she has trouble keeping birds away (like from a cherry tree) make a mobile from scratched, or advertisement CD's, that you have. They are actually suprisingly attractive, making rainbow flashes. Keep the birds away nicely. Or if you have a picture window birds tend to fly into and kill themselves, hang it in front of the window and save the birds that way.