> Beside http://www.rubygarden.org/ruby?RubyWithoutRoot is
> there any tutorial to help me really install ruby on linux
> without root access.

If you run Linux on your machine, you might want to use
AllInOneRuby [1] to create allinoneruby.bin, which is a big
binary embedding the Ruby interpreter and the runtime
environment, and copy this file to the machine of your
provider. I've done this several times. Works flawlessly as
long as your GCC-version isn't newer than the one of your
provider...

In one xterm:

 $ ruby allinoneruby.rb
 Stripping...
 Creating allinoneruby.bin ...
 $ tar c allinoneruby.bin | nc -l -p 1234

In another xterm:

 $ ssh erik / ssh.my.provider -R 1234:localhost:1234
 erik / ssh.my.provider's password:
 erik / shh.my.provider:~> nc localhost 1234 | tar x
 erik / shh.my.provider:~> echo "p 1234" > test.rb
 erik / shh.my.provider:~> ./allinoneruby.bin test.rb
 1234

That's how I do this. No installation, no admin things. Just
one Ruby executable.

gegroet,
Erik V.

 [1] http://www.erikveen.dds.nl/allinoneruby/index.html