Rubik's Cube Earth
If regular Rubik's Cubes just aren't tough enough for you, try the Rubik's Cube Earth. It costs about $20, and should be significantly harder than regular Rubik's Cubes because it lacks the distinguishing colors. Plus, you also have to know what the Earth actually looks like. If I solved this thing I'd just turn it a few times and yell "Solved!" Then when people asked me why Canada was bordering Japan I'd call them ignorant and tell them to maybe take some geography lessons.