Associate Curator Jenny Robb put this info in a comment, but let's copy it here so more people see it:
Thanks for asking how to contribute to the Schulz Challenge. People can donate online with a credit card at: https://www.giveto.osu.edu/igive/onlinegiving/search_results.aspx?fundnum=313023 or send a check to the The Ohio State University Cartoon Library and Museum, 27 W. 17th Avenue Mall, Columbus OH 43210-1393. Please indicate “Schulz Challenge” on the check.
Remember, all donations will be matched dollar for dollar by Jean Schulz.
Thanks for your support of this exciting project!