ApplySyntax is a plugin for Sublime Text 2 and 3 that allows you to detect and apply the syntax of files that might not otherwise be detected properly. For example, files with the .rb extension are usually Ruby files, but when they are found in a Rails project, they could be RSpec spec files, Cucumber step files, Ruby on Rails files (controllers, models, etc), or just plain Ruby files. This is actually the problem I was trying to solve when I started working on this plugin.
DetectSyntax was originally created by phillipkoebbe. In his words, these are his credits:
It all started by forking the plugin created by JeanMertz (1). I modified it quite extensively until I ended up with something entirely my own (2). @maxim and @omarramos commented on the gist and suggested it should be part of Package Control. As I had created it solely for my own consumption, it seemed a bit "hard-coded" to be valuable as a package, but then I took a look at SetSyntax (3). and saw how using settings would make it very flexible. That set me on the path that led to DetectSyntax.
https://facelessuser.github.io/ApplySyntax/
ApplySyntax is released under the MIT license.