There are quite some international spots which are common to be visited by mostly expatriates. UN has always published recommended restaurants or bars which are considered as relatively safe (usually with armed guarded and thick tall walls). However following the security guidelines are the most important as "don't look any problem if there aren't any". Generally curfew will start from 12.00 pm to 06.00 am.
Dress Code: Outside international restaurants or bars please wear muslim woman's clothes to respect Afghans culture: headscarf, no tight jeans or shirt, no boot shoes. Putting double size of your normal size is recommended. My size is 8 but in Afghanistan I wear size of 12 or 14. As long as it is baggy style, men won't stare at women.
Inside the spots, proper dress is acceptable.
In the later evening the streets are basically empty, and often electicity is off around downtown. My first evening in Kabul I came back to my hotel at 11p, and the gate was locked, and we had to rattle it to get in. I thought at teh time there might be a 10p curfew in the city though I don't know the actual situation. Basically, there is not much to do. If you're staying close to Chicken Street (e.g. The Mustafa Hotel), you can use their internet, or head to this great 24 place (they actually close at 4am). The price is 100 rupees per hour (a little pricey), but the speed is great.
Dress Code: Casual permitted
Try to get invited to a family home for a tradtional dinner. You need to experience what it's like being the guest of someone in Afghanistan. A celebration of some kind is even better, maybe a wedding party. You will probably find live music and all guests dancing, one by one. Be prepared to get up and give your own performance!
Dress Code: Same as in the streets, covered. Bring some sweets, flowers or a small gift if you're going to a wedding party. If you are the guest of someone you will most probably receive a gift yourself before leaving. Commonly a handkerchief.
When it comes to nightlife, Kabul could be quite boring. It was impossible to go out after dark in Kabul some years ago, and now, it's still not a good idea to linger the city after sunset. So when you visit Kabul, bring some more books to read in your hotel room to keep you of getting bored, or travel with a nice and humorous travel companion. I cant imagine if I were alone in my hotel room in Kabul. It could be deadly boring.
But eating at Chinese restaurant or Khyber Restaurant on Pasthunistan Square could be interesting also, if you have the budget. Sometimes they have Afghan dances (might be just a wedding party or something) in the Khyber Restaurant. We encountered once, and it was very loud evening dance there.
Yea, it's like 15 rupees to go see a bad Indian flic. I sat through about 1 hour of one.
Dress Code: Dress down okay
a few cinema halls are back up- they show indian films usually, and those are a big hit with afghans!