My favourite "I have nothing in the fridge" meal to make is rice. I usually add spices and beans to my rice, while it's cooking, to enhance the flavour. You can add anything to rice, and make it ever so delicious.
Today's lunch - rice and beans, spiced with cumin, chili powder and garlic salt (1 tsp of each, which I add to the water), topped with roasted zucchini and red onion (both of which I found looking slightly sad in the bottom of the fridge).
It's topped with a little bit of Valentina hot sauce. Pretty much the best tasting hot sauce I've ever put in my mouth.