Muck out with both hands,
start opening doors with your non dominant hand,
try doing the ironing / washing up / drying up with your other hand,
note which leg you step up first on the stairs and start to use the other instead
brush the yard with your broom in the opposite hand - you can progress to doing this in trot and canter doing flying changes in the canter once you are up to it whilst switching your broom from one side to the other

May all sound daft (you can tell what kind of crazy life I lead !) but it does work as it starts to build your neurology and coordination on your weak side.
I am sure others will have some more sensible options with regard to exercise but the above is all stuff that you've got to do anyway so easy to fit into your routine !
good luck xx

PS am loving the book thanks xx