Not many people do cgi programming (especially with C) anymore, but it will teach you a lot about Linux and programming. You will have to get a working web server for one. Configuring Apache on Ubuntu should be a good learning experience. If you can also get a working database server such as PostgreSQL (my preference) or MySQL working with your website, you will know the basics for building a real web-based application.
Not many people do cgi programming (especially with C) anymore, but it will teach you a lot about Linux and programming. You will have to get a working web server for one. Configuring Apache on Ubuntu should be a good learning experience. If you can also get a working database server such as PostgreSQL (my preference) or MySQL working with your website, you will know the basics for building a real web-based application.