I thought, why not make an 'Apache Filter Debugger'. The idea is to make a nice Gtk2+ GUI that fakes a request and all structures used by Apache. It would allow you to set all parts of a request, then specify the input, and a filter chain to run the content through. After each step you can view the before and after in a multipanel screen, making it easy to see what came in and out. Just a pipe dream right now, but it could save people hours debuging on filter modules in Apache 2.
In other news, ApacheCon 2004 has openned with a Call for Participation. I am thinking about 3 possible sessions. First up 'XML/XSL and Apache Modules'. I was thinking I could focus on mod_transform and modsvnview for this session. My second idea is 'The 2.1/2.2 AAA Framework' where I could take an indepth look at modauthndbi, and possibly authentication caching. My final possible session would be about 'Mass Virtual Hosting in Apache 2.0'. For this I could combine the work of modvhostdbi, moddbipool and mod_hwshare. I do not know which sessions I want to submit to ApacheCon yet. I think I will write a small outline for each, then decide which ones to go forward on.