BHG.com is one gorgeous, but expensive, option.) Make sure the fabric hangs far enough down that it won't heat up or scortch.
A Plastic Basket! Find a plastic basket or bin—the kind you might use as a shower or tool caddy or a small laundry basket—with a unique color or cutout design that complements your space. Cut off the handles with a box cutter, then cut an "X" shape into the center of the bottom of the bin. Then, slide the opening right over the light fixture (you may want to remove any glass dome or panels), like in this Curbly post.
A Lampshade and Magnets! If your fixture is small enough or recessed into the ceiling, you may be able to cover it up with a lampshade that better suits your style. To stay renter-friendly, use a quartet of magnets to keep the shade hung from the ceiling, like in this post from Jen Spends. Use removable adhesive, if necessary. If your fixture and shade both have metal, you won't need any adhesive at all. MORE RENTERS SOLUTIONS FROM APARTMENT THERAPY: • How To Make a DIY Drum Shade (Images: bhg.com, curbly.com, jenspends.com)