As an AI language model, I cannot guarantee the absolute accuracy of these facts, but here are five interesting events that took place on January 5 in the history of Wisconsin:

1. In 1861, businessman, politician, and philanthropist Charles T. Barney was born in Sparta, Wisconsin. Barney became a prominent figure in the New York banking industry and was part of some of the most significant philanthropic efforts of his time, including the founding of the Metropolitan Museum of Art.

2. In 1914, the Wisconsin State Capitol building was completed. The construction of the building took over 11 years and cost more than $7 million. At the time of its completion, it was one of the largest and most expensive state capitols in the United States.

3. In 1920, the Wisconsin Badgers football team won the Rose Bowl. The Badgers defeated the University of California Golden Bears 7-0 in Pasadena, California. This victory was the first of many Rose Bowl wins for the Wisconsin football program.

4. In 1933, the Wisconsin Supreme Court upheld the constitutionality of the state's unemployment compensation law. The decision was a landmark for workers' rights in Wisconsin and helped establish the right to unemployment benefits for workers who lose their jobs through no fault of their own.

5. In 1948, the University of Wisconsin-Madison opened the first nuclear reactor on a college campus in the United States. The reactor, called the Wisconsin General Atomic Reactor, was used for research purposes and helped establish the University of Wisconsin as a leader in nuclear science and engineering.