InstaLooper a simple looper with integrated fx, made especially for live music.
Instalooper is a free effect for Mac OS X, Windows and Linux for looping the incoming audio on the fly: with trigger buttons to loop the audio, and knobs to change the loop duration.
It is synced with the host. Once looped you can adjust the speed and/or add an effect on the audio loop.
Instalooper is available for Windows, OS X and Linux.