Find a subject to photograph indoors without a flash and set your camera on a tripod. Set lens to f8 or f5.6 in aperture priority and cycle through the ISO settings from lowest (in my case 200) to highest (in my case 6400). What is your comfort level with how high you can go?
I had a hard time finding something interesting in the house worthy of photographing. I did two cycles, one of the carseat and the other of our shoes. During the day I tend to open window blinds to allow in light. I don't feel like I am living in a cave. Though, sometimes the heat is pretty high.
So here are the shoes. :) Much more interesting than the car seat I think. And I needed to run through these quickly as it was during nap time.
I wouldn't mind going up to 800 in the house (that was where the automatic setting took the image at), but that is pushing it. Preferably I wouldn't want to go higher than 400. Though I am impressed with the image quality on my camera at the higher settings. It maybe different at night though with no natural light, though who wants to take images with no natural light? That is not preferential. Natural lighting is the best, and with a flash everything is different...
I played with post production of the ISO 6400 image...