A proxy server for HTTP transport so that one could access the web anonymously. I don't think coding is the problem here; one could be easily hacked out in perl, or you could use CERN HTTPD as a proxy server. I think the problem is finding someone who will offer up their machine as a place to run this service.
It could be run from any user account, like a remailer... The only problem there is getting it to start up after the machine has rebooted, etc. I suppose a procmail recipie or some other .forward magic could be setup so a simple e-mail message to the proxy operator account would start the server if it wasn't running. I would think that running an anonymous HTTP proxy server is much less likely to bring people screaming to your sysadmin than an anonymous remailer. Thus there is a chance that there could be more people willing to put up the service than even remailers... However, while there may be less chance of forceful shutdown due to complaints, an anon-http proxy server would probably consume much more in the way of network resources than a remailer, which will likely lead to many being shutdown once discovered by the sysadmins (although, maybe not). andrew