If you have children, find places where kids eat free or cheap. There is all sorts of places around that lets kids eat FREE on specific nights. Usually you can have one free child's meal with each paying adult meal. Here are a few if you're in the area.
Tuesdays-Pizza Ranch, IHop, Perkins, HyVee Market Grill in Ankeny, Pizza Hut Buffet
Wednesday-Wig and Pen in Ankeny
Thursday-Cozy Cafe in Clive
Saturday-Z'Mariks Noodle Cafe
Sunday-Okaboji Grill, Planet Sub
Other restaurants offer deals during certain days or during certain hours of the day. For example on Wednesdays McDonalds offers reduced price Happy Meals all day, Buffalo Wild Wings offers $1.99 kids meals all day and Applebee's offers 1/2 price kids meals from 4pm to close.
Another way to save some change is to skip the fancy drinks. Sticking with just plain ol' water will save you around $2 per person! You can always look for coupons and offers in magazines or newspapers and even on Groupon. This isn't very fun but you can always skip dessert as well and that will cut a huge portion of your bill down. Or maybe you can just skip the entree and just order dessert!