Politically, the best thing might be to solicit ideas from the club members. That accomplishes a few things: it helps to select something they're definitely interested in, it gives them a sense of participation and ownership in the process, and it keeps you from being the "dictator". 🙂 That being said, it doesn't hurt to throw some suggestions at them.
For web development, some "things to learn first":
Using HTML to mark up a document for semantic meaning. Start to learn how to read and use the W3.org HTML Specification. Get into the practice of using the HTML Validator.
Using CSS to define the visual appearance of your HTML pages (rather than using HTML tables and deprecated attributes). Start to learn how to read and use the W3.org CSS Specification. Get into the practice of using the W3.org CSS Validator.
At this point, you are now ready to look into adding dynamic functionality to your web pages, via client-side programming (e.g.: JavaScript) and/or server-side programming (e.g.: PHP).
