Cambridge in October
Tunisian: Cafe Baraka in Central Square. Try the squab. 36 hr advanced notice
Afghani: The Helmand in East Cambridge
Jamaican: Ortanique in Huron Village
Thai: Brookline is just over the river. Try Dok Bua or Rod Dee or Khao Sarn
Szechuan: Mary Chung's in Central Square
Japanese: Cheap and decent options like sushi, ramen, udon in the Porter Exchange Mall in Cambridge, MA
Indian: Namaskar in Davis Square, Somerville
Tamarind Bay in Harvard Square
enter 'cambridge thai' or 'cambridge indian' or whatever into the search window and i think you will come up with alot. also somerville is right next to cambridge and has many of boston's excellent ethnic places. also, for CHs to be able to better help you, you need to give more info about your visit to camb- in what part of camb are you to be staying? and do you care about distance/transportation/pricing/ambience for your restaurants?
Chez Henri between Porter and Harvard Squares is THE place to go for cuban sandwiches. They are about $15, but big enough for two people to split.
Punjabi Dhaba in Inman Square is a quick, mostly takeout Indian restaurant that has some of the best Indian food in the Boston area. They have a few tables upstairs that look out over the square.