Preferably ones that will provide physical exercise and mental stimulation-if possible. Also; ones that would be good for a medium sized dog(that weighs about 45lbs). It hasn't snowed where I live yet, but I'm sure it will soon and when it snows here-it snows a lot. So I'm trying to find activities to do with my dog now so I can plan for them and get the correct supplies, if necessary. If anyone has any suggestions, it would be much appreciated. Thank you in advance.