How to make a crossover cable out of a spool of ethernet cable, crimper and connectors?

We have cable, a crimper and the RJ45 connectors laying around our office. I know the TX and RX are switched in a crossover cable. But is it as simple as taking regular ethernet cable and swapping those two little wires on one end? Or is it specially constructed all the way through the cable, and my making my own in this case will ruin the "CAT 5e" rating or so? Anyone know? In worst case I may just give it a shot and see... Thinking about it logically I can't see how there can be anything else to it except flipping those two little wires on one end.