Of course, as famous as the Festival is the military Tattoo. Now this sort of thing isn't really my style but when I went I paid for a package which included the Tattoo as part of the deal so I went. There are really only two pieces of advice that I can give to anyone considering attending. The first is to go and see it. True its all very loud and bombastic and the inclusion of motorcycle displays and troupes of Irish and Scottish dancers largely fail in their objective of making it less militaristic. Nevertheless it is all amazingly colourful and spectacular and probably the best conceived and performed entertainment of its type in the world.
The second piece of advice is one I wish someone had given me. I had spent the best part of the day before the Tattoo drinking large quantities of beer. (Well when in Rome...) This was a MISTAKE. So many people are crammed into the Castle for the event that leaving your seat is an impossibility. The show is spactacular but possibly not as spectacular as the bladder control needed to watch it. So the second piece of advice is that there will be plenty of time for drinking when it's all over - trust me you'll feel better for avoiding it beforehand.