Vidgamer838 has recreated the Rat’s Nest multiplayer map from Halo 3, complete with the trio of UNSC Marines voiced by Firefly and Serenity cast members — Alan Tudyk (Wash), Nathan Fillion (Mal Reynold), and Adam Baldwin (Jayne Cobb):
This is an entry for the August-September Contest in the LEGO Halo group on Flickr (click pic below to see entries):