Go to the store and buy dog food.
raw egg and rice (cooked rice) always goes down well
Cheerios and pepperoni
Cooked rice and chicken is a good idea. Also peanut butter and wheat bread will work as well. Worse comes to worse try pasta. (Or cat food, but it has more fat than dog food and can give them the squirts)
Chicken breast (cooked) and rice (cooked too - LOL!) - the vet suggested it... and when we don't have that - dry, non-sugary cereal and some cheese was what we did until we could get to the store - not the best alternative but usually we weren't out for that long (plus he LOVED cheese!).