We hear a lot about Mars, Jupiter, and Saturn, which is because we have exceptionally fancy hardware floating about and, in some instances, cruising on the surface of these planets. The planets that lie farther away from the Sun do not get quite as much attention, but they may soon, as NASA is presently spitballing some missions which will give us a much better look at Uranus than we have ever gotten.
The theoretical assignments, which would see NASA spacecraft heading into both Uranus and Neptune, are of huge scientific advantage. The idea is to ascertain what the planets are made of, have an idea of the atmospheric composition, and take a great deal of excellent photographs, too. Researchers expect to examine the weather and general climate of the planets, while determining how they fit into the general makeup of our Solar System.
A similar option exists for Neptune, although the actual details of the assignment(s) would have to be fully fleshed out before it comes anywhere near an official proposal.
The assignments are still a long way in reality, both in funding and in timeframe. NASA states that 2030 through 2036 will be feasible to get a Uranus trip, even though a Neptune mission would have to take place before 2030 or after 2040, because of the timing of a gravity-assisted increase around Jupiter.