Very Special Relativity is by far the best quasi-technical treatment of special relativity that I have found. The author, Sander Bais, uses Minkowski diagrams on nearly every facing page to illustrate the facts and apparent paradoxes of special relativity. He provides geometrical demonstrations (‘proofs’ in a very restricted sense) of time compression and space dilation.
Most importantly, the consistent use of Minkowski diagrams gives the reader a good handle to remember and reproduce the results of relativity theory.
This is an excellent book for anyone with a grasp of elementary Euclidean geometry who wishes to get a better understanding of the special theory of relativity.