A zendo is not a peaceful haven, but a furnace room for the combustion of our delusions.
ZENDO RULES 
General etiquette
Don't worry about remembering all of the above - you'll pick it up as you go along!

Attire and appearance
- Wear loose, comfortable clothing in dark, solid colors.
- No distracting or revealing attire.
- Shorts or jeans are not appropriate zendo attire. We recommend gi pants or scrubs or other loose-fitting pants in dark colors.
- No apparel with patterns, large logos or images or bright colors.
- No hats.
- No bright, large or otherwise distracting jewelry.
- No visible tattoos if it is possible to cover them.
General etiquette
- At the Sunday and Wednesday meetings, be seated on your cushion, or
standing formally in front of it, no later than ten minutes before the
scheduled starting time.
- Before entering the zendo, remove your shoes and place them neatly in line outside the door.
- Turn off your cell phone.
- Bow with hands in gassho (palms together in the attitude of prayer) when entering or leaving the zendo.
- If you arrive late and chanting has begun, do not sit down. Remain standing by the door with your hands in gassho until all chanting is done, then bow to the altar, go to your seat, bow to your cushion, bow to the sangha and sit down.
- If you arrive late and zazen has begun, enter quietly and sit down, following the forms above.
- During zazen, sit still and breathe silently. If you feel like moving, just observe the impulse to move. If you are unable to sit still, stand up and quietly bow out of the zendo with hands in gassho.
- Involuntary coughing is obviously unavoidable. If you feel like coughing, but don't have to, just observe the impulse to cough.
- If your nose runs, let it run. Just observe the impulse to wipe it.
- Do not attend a meeting while under the influence of alcohol or drugs.
- No firearms or other weapons are permitted inside the zendo.
- The zendo is a place of compassion and respect; no aggressive or insulting speech is permitted.
Don't worry about remembering all of the above - you'll pick it up as you go along!