You basically have two options. If you're just modifying a single param between test, it might be easiest just to do something like:
before(:each) do
game = FactoryGirl.create(:game)
end
it "does something" do
get("/game/1").should route_to("game#show", :id => "1")
end
it "does something else" do
game.update_attributes(:param => "value")
get("/game/1").should route_to("game#show", :id => "1")
end
Otherwise, you could set up a factory girl sequence and do a fresh FactoryGirl.create in each spec.