Great question! Here at the QSU we like to use iTunes to play loops. It's cool and easy. (iTunes comes with all Macs, and you can get it free for Windows too at http://www.apple.com). Here's what you do in iTunes:

1. Download the beat from the QSU (you'll get an .mp3 file)
2. Drag the .mp3 file onto iTunes (the beat should come up on the player)
3. Click on the iTunes "Controls" menu, then select "Repeat"/"Repeat One."

The beat will loop continuously. Yeah.