If you're heading into Chicago to report on the NATO events there's only a few places for camera rental and repair inside the city proper, and only one place that's open on Sundays. Here are some options. These stores are going to be your source for any last minute purchases of any kind. Bags, covers, lens rentals, flash accessories, straps, batteries, lights, stands... you name it. For simple things or a cheap SD card you can also visit any of the number of chain stores. Since most of the camera shops in Chicago are closed on Sunday, you won't be able to get DSLR batteries, good SD cards, or any custom accessories.The NATO march on Sunday will be passing through a mostly residential area without any big box stores or camera specialty stores. In a pinch, you might find a Walgreens or CVS drugstore, where you'll be able to buy AA batteries and painfully slow Class 4 SD cards of the 8GB and under variety. I wouldn't expect to find high speed SD (SDHC, SDXC) or CF cards anywhere.