On the NetTuts site there's a tutorial posted helping you get familiar with Doctrine 2 (the ORM) and how to integrate it with a Laravel 5 application via a simple service provider.

As a PHP developer, you might have come across the term ORM. ORM is a way to work with databases in the same way you work with classes and objects. If you were to delve deeper into how web applications are designed and built, after doing some exploring in their ORM you would find two well-known patterns: Active Record and Data Mapper.

[...] With Data Mapper the in-memory objects needn’t know that there is even a database present. They need no SQL interface code or knowledge of the database schema. One such solution is Doctrine.

The tutorial walks you through some of the basic concepts in using the Doctrine 2 ORM including Entities and Repositories. Also included is how to pull it in via Composer and update your Laravel configuration to use this bridge library for integrating it into your current application. Code examples are included showing you how to build out an entity, repository and a validator class for a basic blog post.