PEERING is an environment where researchers and educators can play with BGP announcements in a real but sandboxed environment.

Description from the website:

The long-term goal of the PEERING system is to enable on-demand, safe, and controlled access to the Internet routing ecosystem for researchers and educators:

PEERING for researchers. Today, it is hard for researchers to conduct Internet routing experiments. To perform a routing experiment, a research institution has to obtain Internet resources (IP addresses and ASNs) and establish relations with upstream networks. PEERING eliminates these obstacles and provides researchers controlled on-demand access to the routing ecosystem.
PEERING for educators. Educators can use the PEERING infrastructure in teaching students the Internet routing architecture. The students access to live BGP sessions to multiple ISPs.