This repo contains a very minimal playground to experiment with BGP using BIRD. This is meant to accompany the article at http://packetfire.org/post/intro-to-bgp/ however there is nothing stopping you from using this as a toy environment to play with routing.
Alternatively a similar environment is provided that leverages full virtualization using vagrant as the provisioner. This repo can be found at https://github.com/ncatelli/bird_examples.