Can Unix Mount .TAR.GZ and .ZIP Files?

rhadc asks: "We can mount filesystems. We are constantly downloading .zip files and .tar.gz's. Why can't we mount .tar.gz's or .zip files? Mounting compressed packages and archives would make installation of software a little easier. Depending on how it was implemented, it could also require less disk space than the current method: Download, unzip, work/play. I've been a C programmer for a while, although taking on a large filesystem-type project isn't something I have time for, right now." It's just a matter of some enterprising (or bored) hacker writing file system drivers which use /dev/loop*, isn't it? Are there any projects looking to do something like this? Programs that cheat and actually untar the file to a teporary directory don't count.