silly, as in "silly mid-on" literally means so flipping close to the batsman you'd have to be silly to stand there - a few more (sorry it's been a while so i can't remember them all) mid on and mid off - the on-off business comes from the hand of the batsman - if the batsman is right handed then by the way he stands, he would find it easier to hit balls to his left [on side] (across the body) than to the right [off side] (away from the body). Obviously the rule is vice versa for left-handers. Therefore the mid-on mid-off stands midway between the batsman and the boundary behind the oncoming bowler, either on the on-side or on the off-side (sorry this is hard to explain without diagrams). Long mid-on and long mid-off, stand nearer the boundary. Square leg - stands in line with the umpire on the on-side (leg side), forming a right-angle/square with the bowler batter and himself. Gully - other side of square leg but a bit behind the batter (almost like a nunmber 5 slip) - an educated guess is that this is a common channel or gully, for the batter to hit to. fine-leg is behind the batsman (usually on the boundary) on the on-side, in case the batsman hit's the ball finely (and deflecting it behind him). 3rd man is same thing but on off-side (I don't honestly know why it's called 3rd man)..... what else........ wicket keeper - obvious why he's named that, slips - stands near the wicket keeper for when the batter gets fine edges (again i dunno why they're called that). Any more you want to know?
You say this hard to explain without diagrams, Darth. I've got the diagram in front of me and I'm still having problems with it. I suppose if you work clockwise you can show the outer positions, starting from the '1' of the clock-long off, deep extra cover, extra cover, cover point, deep third man, deep fine leg, deep square leg, deep square leg and long-on; but the rest of them seem to be a mass of names!