http://klik.atekon.de/wiki/index.php/User%27s_FAQhttp://klik.atekon.deHaven't tried this, but it looks pretty neat. It can make Linux a few degrees less scary for your Aunt Petunia. Klik uses script "recipes" to roll up the binaries, dependencies, etc of a package into a standalone executable which can be run from anywhere.
Only the client (20K) must be installed as Root, programs can be installed with User privileges. The interface for downloading/installing/running is through the browser. Don't like a program, delete the executable, no harm, no foul (unless of course, its data/config paths are hardcoded, you'll have to be mindful of that if you're say, test driving another instance of an already-installed app).