You may want to purchase or build a squirrel feeder to put out in your yard. If you Google "squirrel feeder plans" you will find plenty of sites offering instructions on making a feeder. Here is one site that offers links to plans for several different designs. One of the advantages of having a squirrel feeder in your yard is that it can help divert the squirrels from your bird feeders or your vegetable garden. You can also easily find plans for nest boxes designed for squirrels.
You can also visit a local park or nature preserve and watch the squirrels, birds and other wildlife on display there. If there is a wildlife rehabilitation center in your town, you can inquire about donating money or supplies, or volunteering. Here is a national list of wildlife rehabbers in the United States.
Squirrel Appreciation Day is an excellent time to think about things that you can do to help preserve the environment and the habitats that are so important to squirrels and other animals, as well as humans. There is a wealth of information about ways to do this, only a Google search away. You might start here for some practical and relatively inexpensive steps you can take to help the planet.
Squirrel Appreciation Day is an important time to think about what we can do to help squirrels and all wildlife that we share this planet with. The most important thing, though, is not just to appreciate our bushy-tailed friends one day out of the year, but to make every day Squirrel Appreciation Day.