When it's time to work out, you wouldn't don decades-old sneakers or use equipment left over from Jack LaLane's boyhood gym. So why keep bringing that bulky music player along? The Nike PSA/Play 120 weighs a scant 3 ounces. The rounded design slips easily into a pocket or attaches to an arm band (included). S3 (541/967-2450, www.riohome.com ), makers of the Rio MP3 player, developed the $300 PSA/Play 120 with Nike, which apparently is moving its quest for global domination beyond athletic apparel and Tiger Woods ads. PSA/Play's expandable 64MB built-in memory plays two hours' worth of MP3 and Windows Media (WMA) files, enough to accompany the most grueling workout. The digital-display remote makes choosing a playlist easy, even on-the-go. After all, those 30 minutes on the StairMaster are hard enough without your MP3 player weighing you down.