24 hour "layover" in Uruguay

After a little over 2 weeks in Argentina, we are on route to our 5th country in South America. Interestingly enough, our original travel plans did not include Uruguay but as I've learned over the past 5 months, you have to be flexible and resourceful while traveling. When searching for our flight from Argentina to Peru (our originally planned final destination) we discovered that flights from Argentina to Peru were considerably more expensive than flights from Montevideo, Uruguay to Peru. To avoid this extra cost, we left Argentina this morning and took a 1 hour ferry to Colonia, Uruguay and a 3 hour bus ride from Colonia to Montevideo. Our flight out of Montevideo will leave tomorrow afternoon at 2 pm so we have about 24 hours in the country but plan to make the best of it!