Toolbook is the quick multimedia prototyping tool there, but Visual Basic is the most popular programming environment, probably in the world. The World Wide Web is certainly a great attraction across many audiences. The tough part of WWW is getting interaction. Java is a possibility, but it takes some significant programming effort. JavaScript is a scripting language for Netscape clients, but it's still a little buggy.
Programming is hard for kids.
Spreadsheets are easier and work for a wide variety of problems that kids might want to tackle, but they're still not all that easy either. I've been imagining a simulation environment with great images that, underneath, was just a spreadsheet. At a lower level of scaffolding, equations could be entered so that values didn't have to be entered by hand. At a still lower level, you could create the connections between the spreadsheet and the representations yourself. There are lots of groups on campus that have a whole bunch of tools and students waste much of their classtime figuring out how to integrate the tools.