Among the various fanatical Christian movements springing from the earth these days, a name that is being associated with a number of these groups is "Joel's Army." Similar to the various factions of the Christian Identity movement, there's no single leader of Joel's Army; rather, it's a number of loosely-organized Christian militia groups who follow the same general ideology.
The name "Joel" comes from the book of Joel in the Bible, Joel 2:1-11, beginning with: A day of darkness and gloom, a day of clouds and blackness. Like dawn spreading across the mountains a large and mighty army comes, such as never was of old nor ever will be in ages to come. These folks take this statement as a prophecy, that Christian militarism is rising.
Dark Christianity summarizes Joel's Army as follows:
- "Joel's Army" is a separate strain of dominionism that is largely popular in pentecostal and neopentecostal churches (in particular, the Assemblies of God, Foursquare, and "independent" neopentecostal megachurches) that states the US must be taken over--forcibly, if necessary--to not only convert a critical mass of people to dominionist Christianity (non-dominionist faiths are not seen as "Christian" enough) but to ensure God keeps blessing the US; "Joel's army" theology in particular has close links to "name it and claim it"/"Prosperity Gospel" (just watch darned near any televangelist for examples) and "deliverance ministry" movements (many of which are linked to fairly severe types of spiritual abuse); examples of "Joel's Army" in the media include the movie Jesus Camp (held at an Assemblies church linked to the "Joel's Army" movement) and Marguerite "I'M A GOD WARRIOR!" Perrin; the Left Behind book series (and movie, and video game, and so on) is a fictionalisation of how "Joel's Army" theology concerning the end of the world. 
So if you're involved in a flamefest with hardcore religious fanatics and you find they're into "Joel's Army," you've got an idea of what you're in for.