Why "installing" almost anything requires "access rights" is still confusing to me. I don't understand why there's not been a movement to 'install' things in to my own home directory structured, vs "c:\program files" on windows "/usr/bin" and such on linux. - Fall back to c:\mystuff or ~/bin.

ClickOnce[1] does this.

Some other apps have their own mechanisms to do the same, e.g. Google Chrome.

I don't think it's a good idea though, as it makes those apps more susceptible to being modified by malware.

[1]: http://en.wikipedia.org/wiki/ClickOnce