It's a walk (half mile), but http://www.barcelonatapas.com/indianapolis/ is pretty good. Has a lunch buffet M-F/11-2 that makes it quick and affordable. We went last year on Thursday during a lull in our scheduling.
If you like sushi indymikado.com is right next to the convention center.
And last year we just walked in, with no wait at Harry & Izzy's. It was a fine meal, if a bit pricey. I plan to go back.
If you are willing to walk to Mass ave, meshrestaurants.com (1.5 miles). I quite enjoyed my meal there. Mass ave has a bunch of interesting places, any one of them might make a nice sit down Wednesday night get together with friends.
As far as the tamale place, go nachos. It makes a nice place to stop for lunch on Wednesday before heading into downtown (they have south side and west side locations). Quick, no fuss. Two people can share a large nacho for 9 bucks so you can make it affordable if you desire. I wouldn't tell you to make a special trip, but it beats the hell out of taco bell or McDonald's if you are driving in hungry.