Participants compete more for the honor loudest than fastest in the Karaoke 5K, singing along to the tunes coming from their handheld radios as they stroll through the race. Each radio plays the same playlist of popular sing-alongs, encouraging runners to sing into toy microphones as they go, which adds rock-star flair less extravagant than stretch-limo rides to the finish line. The race aims to raise $10,000 for Habitat for Humanity, a nonprofit that builds homes for people in need.