require 'gtk2'

Gtk.init
w=Gtk::Window.new("click my button").set_width_request(300)
w.add(@l=Gtk::Button.new)

Thread.new{
	i=0
	while true do
		i+=1
		@l.set_label(i.to_s)
		while (Gtk.events_pending?) do Gtk.main_iteration_do(false);end
		sleep 0.2
	end
}

w.show_all
Gtk.main