diff --git a/lib/simplekit.rb b/lib/simplekit.rb
index d55d1c8cbb132e965ee2a1db6c0842d9d6d81da9..7291467fddc109407a0a50a87c777144cdaebaf4 100644
--- a/lib/simplekit.rb
+++ b/lib/simplekit.rb
@@ -1,4 +1,4 @@
-require 'rubygems'
+require 'rubygems' if RUBY_VERSION =~ /^1\.8/
 require 'skewheap'
 
 # Including SimpleKit in your simulation model gives you methods +:run+,
@@ -12,19 +12,19 @@ module SimpleKit
   # Run your model by creating a new +EventScheduler+ and invoking its
   # +run+ method.
   def run
-    @mySim = EventScheduler.new(self)
-    @mySim.run
+    @my_sim = EventScheduler.new(self)
+    @my_sim.run
   end
 
   # If a method doesn't exist in the model class, try to delegate it.
   def method_missing(name, *args)
     if DELEGATED_METHODS.include?(name)
-      @mySim.send(name, *args)
+      @my_sim.send(name, *args)
     else
       super
     end
   end
-  
+
   # Class +EventScheduler+ provides the computation engine for a discrete
   # event simulation model. It uses the +SkewHeap+ RubyGem as a priority
   # queue implementation for the pending events list.
@@ -51,7 +51,7 @@ module SimpleKit
     #   - +args+ -> an optional list of arguments to pass to the event
     #     at invocation time.
     def schedule(event, delay, *args)
-      raise "Model scheduled event with negative delay." if (delay < 0)
+      fail 'Model scheduled event with negative delay.' if delay < 0
       @event_list.push EventNotice.new(event, @model_time + delay, *args)
     end
 
@@ -64,7 +64,7 @@ module SimpleKit
     def run
       @model_time = 0.0
       @user_model.init
-      while (current_event = @event_list.pop) do
+      while (current_event = @event_list.pop)
         @model_time = current_event.time
         @user_model.send(current_event.event, *current_event.args)
       end
@@ -77,23 +77,23 @@ module SimpleKit
     end
   end
 
+  private
+
   # This is a private helper class for the EventScheduler class.
   # Users should never try to access anything in this class directly.
-  private
   class EventNotice
     include Comparable
 
     attr_reader :event, :time, :args
-    
+
     def initialize(event, time, *args)
       @event = event
       @time = time
       @args = args
     end
 
-    def <=> (other)
+    def <=>(other)
       time <=> other.time
     end
   end
-
 end