So after talking about what rules I use in part 1, today I'm going to look at every DM's crutch, the DM screen.
In the early days of my playing the hobby, I recall using the monochrome adventure module covers to separate my duties from the rest of the players. Mostly used to hide the dungeon map and the map key from the players, this separation has somehow evolved with Role-playing games and appears in some form in almost every genre of the hobby and in some cases a bit overkill.
I'm not quite sure where the Game Master screen came from, I don't recall reading about it in the Holmes blue rule-book or in the Dungeon Master's Guide but somehow, in the early days of the game, it became part of standard table-top paraphernalia. The earliest version I came across put out by TSR was around 1979 and came with 2 durable screens. This was for the Advanced version of the game. With the release of 1st edition D&D, the many complicated charts within the DMG and the Player's Handbook made it almost a necessity to have quick access to these finer points of the rules to keep the game flowing.When I was a young 1st level DM at the ripe age of 10, I enjoyed that separation from the players. That barrier was something that I was able to hide my lack of knowledge of the game and my insecurities behind. Now days, I find that separation an annoyance. I like to be as much a part of the table as my group of players are. The separation now feels too distant.
Having said that, I do still have a screen handy. Again, it's only used to separate the map and the key from the players (only when I have to) but also house a few quick reference charts and rules. And like many things in my current campaign, I've created a custom screen.
Since my reliance on the screen is quite minimal I tried to make the screen as small as possible yet still 'hide' the map key and additional notes from the players. What I ended up with was an 17"X 11" screen. The main portion is a full 8.5" X 11" and it is here that I attach my dungeon map with tape or a clip. Since this portion changes often, it is not a permanent element of the screen, just a blank slate to be filled as needed.
On either side of this I have a 4 1/4" X 11" flap where I attach my game charts. These narrow portions have two functions, the first is to make the screen stable, the second is to have a quick r
eference to some of the rules and charts that I tend to use often within the game. I kept them narrow to keep the screen fold-able and compact as well as less of a barrier between me and the players.I created the chart itself with two pieces of 8 1/2" by 11" black foam-core with one adhesive side. I cut one of those sheets vertically in half and attached it all together with black tape. The outside of the screen being the adhesive side, I attach various dungeon artwork taken from various rulebooks. I like the black and white as I find it less distracting that anything in color. It's just there for ascetic decoration at this point and I don't think any of the players even notice it anymore.
With our use of a rules-light game system (Swords & Wizardry) and using an ascending armor class combat system, the charts that I use on my screen are more for little rule tweaks or game additions that I've only placed there to keep the flow of the game going. Things like movement and encumbrance rates (always bog me down) and wilderness encounters and custom moral rolls. See the images below for what I've added to my screen.

Again, I tend not to use the screen unless I really need to, usually when the PCs are delving into some doom filled dungeon. Beyond that I like to join the festivities at the table and have a good time.
Now, all this doesn't mean that I don't have a full reference of charts compiled within a notebook to access at all times, 'cause I do. When running a sandbox campaign, all those charts are your best friends and I'll touch on those in our next installment.