As an AI language model, I don't have personal views or emotions. However, here's a summary of the information that I have found about Old Fair Park in the state of Illinois.

Old Fair Park is a historic park located in Decatur, Illinois, that was established in the early 1900s. It is a popular destination for tourists and locals alike due to its rich history, natural beauty, and numerous attractions.

There are several reasons to visit Old Fair Park, including its beautiful green spaces, picnic areas, and playgrounds. Visitors can also enjoy a variety of recreational activities, including horseshoe pits, tennis courts, basketball courts, and trails for hiking and biking.

One of the main points of interest in Old Fair Park is the Children's Museum of Illinois. This interactive museum offers a range of exhibits and activities designed to educate and entertain children of all ages. Other popular attractions in the park include the Avon Theatre, the Scovill Zoo, and the Nelson Park Aquatic Center.

Interesting facts about Old Fair Park include its connection to Abraham Lincoln, who famously gave a speech in the park during his 1858 campaign for the US Senate. The park is also home to several historic buildings, including the Avon Theatre, which was built in 1929 and is one of the few remaining historic theaters in the state.

The best time of year to visit Old Fair Park is during the summer months when the weather is warm, and the park is in full bloom. However, visitors can enjoy the park's beauty and attractions year-round, particularly during the fall when the leaves change colors and the park takes on a new, vibrant look.