Still working on Dungeon Crawler redirection

Example code

# trying to set a method so I can use @input in other methods
class Input
  def initialize(input)
    @input = params[:input]
  end
end

# collecting the input with a form here
get '/input' do
  @input = params[:input]
end

# this is just when a user loads the page. Probably a better way to call the 
# initial index view, but this is what we're working with so far.

get '/' do  
  @start_room = start_room
  erb :start_room
  # case @input
  # when "go north"
  #   redirect "/dais_room"
  # end
end

# the routing method that generates rooms based on the room method. Really cuts
# down on how many get /'foo' routes I had to build!

get '/:room' do |room_name|
  @current_room = room_name
  #@description = method(:dais_room).call
  #method(:dais_room).call == dais_room
  @description = method(room_name.to_sym).call
  erb :room
  case @input
  when "go north"
    redirect "/dais_room"
  end
end

Line 3 is setting an instance variable, that is only available to instances of the class Input. Which it looks like you never make (Input.new). There are a couple of issues with this, primarily: if this worked, @input would not be accessible anywhere outside of the instance of Input, so line 10 would not work. Additionally, params[:input] is not going to work in that class because params in an instance method defined on whatever class Sinatra requests become, meaning it's only available in Sinatra's get/post/put/delete like methods.

That said, the concept here is good. I think you want to case params[:input] on lines 19 and 34. See https://gist.github.com/1510515 for a working example.