Warning: most of this information was written down off the top of my head, so may be inaccurate or out of date. Corrections (and additional suggestions!) are welcome.
Breads of India takes the Alice Waters approach to Indian food: use fresh ingredients. The menu changes each day, with three veg and two nonveg entrees; the indecisive can opt for a combination plate. Entrees are chosen from across the wide Indian culinary landscape, so keep an open mind. And of course, don't forget to choose from among the breads--all are soft, chewy, flavorful, and fresh out of the oven.
Not quite as cheap as some of the other entries on this list, dinner here may run you $15.
Modulo the meat, you can get your standard Japanese fare here (sushi, tempura), but part of the fun here is in the adventure. There are a number of vegetables on the menu you may never have heard of; don't worry, they're all good. You'll get some miso soup to whet your appetite, and you might want to wash the meal down with Berkeley's own Takara Sake (produced across the street from Vik's).
Japanese food is not cheap, and Cha-Ya is no exception, but you'll have to work to spend $20, and in a pinch you can come in under $10.
Get your pizza ($2 per slice; two is already a decent meal) and your beverage (wine, anyone?) at the counter; if you opt to dine in, enjoy the live jazz acts or wander out onto the Shattuck Avenue median (the closest grassy spot). If you're taking your pizza home and don't plan to eat right away, ask for "light bake"--you'll get a partially-cooked pie needing only a few more minutes in the oven.
Proceed down the outdoor corridor into the courtyard with the tents set up. Your first stop will be the cash counter at the back left, where you will trade dollars for metal tokens which you'll spend elsewhere. You can fork over a token right there for a Thai iced tea or coffee, which you'll probably need given the spiciness of Thai food. Then, get in line for papaya salad, fried chicken, mango and sticky rice, or various curries. A heaping plate of two curries is a steal at $5.
After you eat, you can peek in on the temple services (no shoes indoors, please!) or sometimes watch a cultural performance.
Note on the name: Udupi is a sleepy coastal town in the southern Indian state of Karnataka famous as the home of a prominent temple to Lord Krishna, and as the birthplace of the masala dosa. (These are not unrelated: Krishna is considered a great epicure, so good cooking is an important part of his worship.) Thus any restaurant named for Udupi can be expected to specialize in South Indian cuisine. (Ditto if its name includes the outrageous misspelling "Udipi", but beware of inauthenticity.) Oh, and Udupi is also where my family is from.
Anyway, the restaurant lives up to its name with an all-vegetarian menu
of dosas, uthappam, and the like. It's pretty cheap (no dosa above $6), quick
and quite tasty; the dosas are even better than at Vik's. Grab a "Mysore"
or "Udupi" dosa for an exercise in spice tolerance. And don't be afraid to
eat with your hand(s); that's what napkins are for.
Don't come here expecting chicken tikka masala or lamb vindaloo. The main part of the menu consists of a variety of snack-like items, some familiar (samosas, pakoras), some maybe less so (chole bhatura, bhel puri, dahi papri chaat). Weekdays you can also order a more conventional-looking "special" (one veg, one nonveg option); weekends the menu expands to include idli sambar, masala dosa, pau bhaji, and more. I'm especially keen on the vegetable kathi.
Place your surprisingly affordable order at the counter (don't forget the mango lassi, or Limca or Thums Up for you homesick NRIs), then listen for your name pronounced with an Indian accent through a handheld microphone. Typically the items you ordered will appear one at a time; this is typically instantaneous except during busy times (12:15-12:45 on weekdays, 1-4 PM on weekends), when a masala dosa can take over 15 minutes. Then grab a seat at one of the tables, or at the counter along the back wall, or just head outside and sit on the sidewalk. Remember, substance over style.
When you're done, you can sample some Indian desserts, or head next door for your Indian grocery needs. (Indeed, once the snack bar was a tiny counter at the back of the grocery store, until heavy demand compelled the owner to expand.)