How can I contribute?

Try to contact Ubuntu MOTU team on irc #ubuntu-motu

I assume you mean this? There is already a Debian package (2.10.0), but it is a little out of date.
http://packages.qa.debian.org/m/magics%2B%2B.html

To really contribute you need :

* A working knowledge of the programming language magics++ uses (C++, plus a little FORTRAN and C side)
* A knowledge of things like what a shared library is.
* Some knowledge of things like "makefiles" and terminal usage
* A knowledge of what a debian "deb" package is
* (optional) Some experience with version control (mercurial (my personal fav.),git, or svn)

Of course you can pick these up as you go along. The C++ you probably can't -- you need to be able to write simple C++ programs before you think about packaging.

Heres the run down:

1) Remember that ubuntu usually does a debian import, so whatever debian packages, ubuntu does a mass pull and modifies as needed. So the best place to update it is in debian.
2) Follow these instructions for the current magics version:http://www.moosechips.com/2008/09/ubuntu-rebuild-a-source-package/ . If you do this right it should spit out a new package, which you can install. This will let you know how to build a package that already exists -- useful stuff.
3) Read this http://www.debian.org/doc/maint-guide/ -- it tells you how debian ("deb") packages are structured, and how to build them. Its a bit of a headache, and a good reference guide

4) Extract the magics++ archive into a new folder, then copy across the debian/ folder you made in 2. Keep trying to use the info in (3) to rebuild it.

Seeing as this is a science package, and I am sometimes active in debian-science you can ask at the debian science mailing list:
http://lists.debian.org/debian-science/