At the risk of being downvoted for suggesting PHP, I'm still going to suggest it. You're not going to be cool for learning it but now that PHP has namespaces, a

At the risk of being downvoted for suggesting PHP, I'm still going to suggest it. You're not going to be cool for learning it but now that PHP has namespaces, a built in server, composer, great frameworks and CMS like symfony2 and flow3, and ecommerce platforms like magento and OXID, there's really no limit to what you can do on the server with it. Also, it doesn't hurt your marketability that the vast majority of all webdev jobs require you know it.