You can install this repo which includes the latest versions: yum install centos-release-SCL.
It has the following:
Ruby 1.9.3 (ruby193)
Python 2.7 (python27)
Python 3.3 (python33)
PHP 5.4 (php54)
Perl 5.16.3 (perl516)
Node.js 0.10 (nodejs010)
MariaDB 5.5 (mariadb55)
MySQL 5.5 (mysql55)
PostgreSQL 9.2 (postgresql92)
http://wiki.centos.org/AdditionalResources/Repositories/SCL#head-ecbb469e90133916d0ff83f57dcf05e00674ba7e