This is so cool: the spaceprob.es website tracks all space probes currently active in and around our solar system. (Well, all human space probes, anyway :)
From this you can learn that ... Voyager 1 is the furthest from earth, but Voyager 2 was launched just before it, and that only one probe has visited Uranus or Neptune (in 1979), and that DSCOVR, the most recently launched (by SpaceX!), is destined for the infamous L1 point between the Earth and the Sun.
And that there are only 29 such probes in existence. Or depending on your point of view, that there are 29! probes. How many of these could you name? How many do you recognize?