Getting your bearings right

High Street runs North-South. Imagine facing high street while standing at the Ohio Union (conference building) or the residence halls (where you stay). Then, South is to your right on High Street and North is to your left. High Street is the east boundary of the university campus.

Restaurants

At the Ohio Union (conference building)
The conference building (Ohio Union) has a couple of restaurants, a coffee shop, and a food court, all on the first floor. The two restaurants are Sloopy's Diner and Woody's Tavern. The coffee shop on the first floor is Express-OH and the food court is called Union Market.

Very close to the Ohio Union, just off campus
There are numerous restaurants of varying quality and price around campus, especially on High Street, that the students eat at. Here are some reasonable ones. Most are not meant to be fancy and are quite basic.
Diaspora (Korean)
Mad Mex (sort of Mexican from Pittsburgh, possibly loud)
Adriatico's (Pizza)
Mughal Darbar (North Indian)
Alana's (American, somewhat fancy, call ahead?)
Yau's Chinese Bistro (Chinese)
Kroger. Big grocery store, open until 1 pm. Just 10 minute south of campus on High Street.

Short North (keep walking south on High Street).
We recommend that you explore this neighborhood on Wednesday. Numerous restaurants as you walk in this neighborhood. Here's what from Yelp thinks is great. And here are some more, with some overlap with Yelp.
Nida's (Thai)
Northstar Cafe (Organic)
Lemongrass (Thai/Asian fusion)
Happy Greek (Greek)
Martini (Italian)
But just keep walking south from the Ohio Union until you hit something you like. There are also a number of nice art galleries in this neighborhood, although many may close early in the evening.

North Market is a large indoor market, with numerous little food places. But limited hours in the evening (close at 7 pm). Fun if you're killing time during a weekend.

Open 24 hours or very late. In case you want fuel for an all nighter.
Buckeye Donuts (sandwiches, hot drinks, and donuts). Always open. Walk North on High Street from the Union. 5-10 min. Intersection High St and 5th Ave.
Short North Coffee House.  24 hours. Walk South from Union. 10 min. Intersection High St and 5th Ave.

Clintonville (keep walking north on High Street)
Lavash (Mediterranean)
Hounddog's Pizza (Pizza)

Grandview (a different neighborhood)
Aab India (North Indian)
Mazah Mediterranean Eatery (Mediterranean)
Dewey's Pizza
Figlio / Vino Vino (Pizza and wine)
Cap City Fine Diner (American)

Other random faraway places

Here's what tripadvisor thinks is great in Columbus.

Refectory (French, New American)
Lashish the Greek
Udipi Cafe (South Indian)