Get squeaky clean with science with the Portal 2 Aperture Laboratories Shower Curtain! Before Aperture Science became a worldwide leader in science, they were a worldwide leader in shower curtains. In fact, the majority of Aperture founder Cave Johnson's wealth was amassed thanks to contracts with the U.S. military to provide shower curtains to military bases (except the Navy). Rumor has it Cave was exposed to high levels of mercury while developing deadly shower curtains for the House Naval Appropriations committee. This shower curtain, while emblazoned with the Aperture Science logo, probably doesn't contain mercury or radiation. Not if you're in the control group at least. (Pssst, you're in the control group.)
The officially licensed Portal 2 Aperture Laboratories Shower Curtain was approved by Valve, and made from white EVA vinyl. While it's not radioactive, the curtain does feature the aperture logo and text letting you know that it "contains less than 1% mercury." Measures 72-inches long x 72-inches wide.