Does anyone know to how to install Oracle 11g on Ubuntu 11.10?
AskUbuntu.com has this question: How to install Oracle 11g?.
Oracle Database 11g and Ubuntu 11.10 Oneiric Ocelot has some good information.
Here are some obligatory links to the relevant 11g pdf documentation.
Oracle tends to be finicky about requiring specific versions of system libraries. Linux is generally fairly amenable to installing these without breaking the existing libraries, so this is normally fairly straightforward to overcome. Many of the HOWTO documents explain how to obtain and install these libraries.
I've certainly had Oracle running on unsupported platforms (Fedora, Debian for example), and once the correct libraries are present you can just use the standard installer.
This link is to an OTN article that describes the libraries required to install Oracle 11gR2 on Ubuntu.