OK, so you're a high-powered professional type who entertains constantly and can't take the time to change clothes between the gym and your evening commitments. In an inspired moment, you devise a plan to save time by wearing your sweatpants gussied up with a couple of decorative doodads you carry around in your gym bag. Ta-da, instant elegance.
No matter what fabric you make them out of or what you stick on them, including an exorbitant price tag, you just can't make sweatpants into evening or luxury attire. Sorry, you'll just have to wait until you get home to get truly comfy.