The Voyager probes were able to do what they do because of a one in a century alignment which allowed them to get gravity assists and slingshot their way from each one. Orbital mechanics being what they are and the cost of bringing fuel along you have to wait until the planets are just right to do that. Now if you mean just flinging something out into the universe we've done that recently with the new horizons probe which is just now heading its way out of the solar system.