In the first of what promises to be a running series, Ktrey starts with the City Encounters subtable on page 98.
Here's a fun house-rule he offers up that would work great in urban or investigation-heavy campaigns of the sort I prefer to run:
Characters start the game with d4+Charaisma Bonus Contacts. Either randomly roll (my personal favorite) or choose some “contacts” from Subtable: 11. City Encounters. These “contacts” are people that your character knows and who are automatically considered “friendly” for the purposes of NPC Reactions. Remember that Armorsmith in the sample adventure from the Mentzer Basic Player’s Handbook who let your character trade his chain for plate? These NPCs are people have known your character long enough to do you the odd favor or two, and likewise if they needed help from you, you’d be hard pressed to refuse.
I'm not sure I'll use it in my Moldvay/Cook/LL hack (I'm tempted to allow players to invent such contacts as needed based upon their backgrounds), but it's the sort of thing that would fit very well into most of my D&D campaigns.