Mine eat a base of Harlan Teklad lab blocks, and every evening they get a dish of fresh fruit/veggies and other stuff. Some of the stuff that is included:

Soybeans, carrot sticks, cranberries, frozen peas, hard-boiled eggs, fresh walnuts still in the shell, puffed rice cereal, Nutro dog food, cheerios, dried fruits, mealworms (They LOVE those!), steamed chicken, steamed turkey breast, catfish, etc...

I know blue cheese is a forbidden food, I'll try to find the complete list later. Also, the forum at www.goosemoose.com/rfc is an all-ratty forum that I also frequent, you might like it!