Some labs do lots of work in Ruby. It would be nice to stick with Ruby for analysis of your data as well. Kindof like the cas for server-side JavaScript: less friction between code in the server and browser.
in addition to jergason's response, sciruby allows/facilitates:
1. better chaining of commands 2. blocks and enumerators 3. integration with rails and other web services 4. a dynamic community
Why? (just curious) SciPy is mature, popular, and has already been heavily peer-reviewed. Then there are R an Matlab and ...
What does SciRuby bring to the table that makes it stand out from the rest?