Currently I'm in the process of rewriting the old VB6 based HTS application missions. There's a few reasons for this, we no longer have the source code, they're highly platform specific (app 4 anyone?) and the files containing the mac ports are corrupted, but the main reason is that they're essentially useless if you're trying to learn something about reverse engineering.

With the rewrite I'm aiming to make the new challenges focused on learning to interpret assembly language, familiarising people with debuggers and understanding program flow, i.e expect more challenges similar to app 7. However, as I'm the only one working on this, so I'm more or less out of ideas. Here's where you come in, if you have a cool idea for a new app challenge, or better yet some code for a new challenge drop by #hacktthissite on the irc.hackthissite.org or use the IRC applet.

Here are the first four application challenges, they are quite simple but they do illustrate the idea.
[url=www.hackthissite.org/devfiles/oohal/apps.zip]For windows[/url]
[url=www.hackthissite.org/devfiles/oohal/apps.tar.gz]For linux[/url]