During the winter, I basically only walk unless I know I have a good surface to ride on (ie, not grass). Lacey's so clumsy anyway, (her life goal seems to be: "if there's something to slip on, I will find it and slip on it") that I'm really really careful to not put her in situations where we might completely go down. However, luckily for me, I love walking. Lacey has a horrible trot and her canter is ok, just unbalanced, so walking is basically her most comfortable gait! Haha
One thing I like to do it the winter when it's not so nice out and I can't do much more than a walk is go on "adventures." I would ride her to strange places on the property that I wasn't sure we could get out of together and then let her do her 'thang and get us out. She likes solving problems and "saving us" so that works out. It was also good practice for her to realize that the rest of the herd doesn't matter, that her mind needs to be completely on the task at hand. Now that she's home, we go on a trail ride or we wander through my neighborhood and visit people (Lacey LOVES visiting people, they give her treats and love, haha the only problem with that is now she has an obsession with driveways XD ).
My other favorite winter "sport" is riding bareback! I love riding bareback as a general rule but in the winter when all I want to do is walk, bareback (her terrible gaits are basically impossible bareback) is especially great. I like to do all sorts of crazy things bareback. We go on "adventures" bareback so that I can hone my "staying in sync with Lacey, no matter what" skill and it's just generally really great for your balance. This last summer I rode bareback so much that I started feeling one with her when I'd get on. Like, when I rode her bareback, it felt like we were physically connected. It was cool that way, and when I started riding in a saddle again I felt so much more in control of my body for some reason...
Anyway, try doing silly things with her! Winter is the time for bonding with your horse, imo. Do crazy (with a low danger possibility) junk and show your horse your silly, not serious-training, side.
Fabio - 13 year old Arabian/Lipizzaner gelding
Hazel - 14 year old Angora goat
Atticus - 4 year old LaMancha/Alpine cross goat
Rest peacefully, Lacey.