One good choice, a fairly easy walk from the Convention Center (5-6 blocks), would be Zaytinya. Middle East themed small plates (mezze). Run by Jose Andres, one of the area's top chefs. Most everybody loves it, and you should be able to put together something in advance which would be well-received and fits your budget. Book well in advance. Fun for a group. Another fun for an out of town group place, also Middle Eastern (North African to be more precise) and nearby, would be Marrakesh. Fixed menu, cazbah decor, belly dancing. Food's not bad, but don't go for the food, go for the fun. It would also fit your budget, and everybody would be talking about it for a long time. Best Ethiopian IMO is Queen Makeda. Very small, homey, family run place. Definitely not fancy. Skip the menu; just ask Mama to bring out whatever the good stuff is that day. It would be a short taxi ride from the CC.