from Tkinter import *
from random import *
import time
tk = Tk()
w = Canvas(tk, width=200, height=200)
def line(event):
    x1=0
    x2=0
    x3 = randint(0,200)
    x4 = randint(0,200)
    w.create_line(x1, x2, x3, x4)
w.bind("<Button-1>",line)
w.pack()    
mainloop()