My preferred languages are Ruby and Perl, although I write PHP code quite often too. I've had a full-time job as a backend developer for about 5 years.
I'm familiar with a pretty wide spectrum of technologies in backend technology stack: relational databases (MySQL, PostgreSQL), NoSQL (MongoDB, Redis), message queues (RabbitMQ). Most of the code I write is for Linux, I'm pretty comfortable with Linux and can do server setup and some common sysadmin tasks.
Currently I'm mostly looking for part-time contracts.