There's no one answer to this question, as what men wear with gray sweatpants will vary depending on their personal style. However, some general tips that may be of help include wearing darker colors on top to add some contrast and injecting some life into a typically drab outfit, like opting for a colorful shirt or sweater. Alternatively, you could go for something that is more flashy and in-your-face, like a bright belt or a colorful shirt. Ultimately, the key is to find something that flatters your unique style and makes you feel comfortable and stylish at the same time.