So today I received my SP-303 (finally!) and have been playing around with it since I'm home. And while messing around with the "Mark" button, if the sample plays and you quickly press the mark button twice, it will sort of create that DJ FX Looper effect. The bigger the interval between pressing the mark button, the bigger part of the sample will be looped. (duh.)

Note that the sample must be on "Loop" mode!

The only downside is that it goes further where you marked the end point..

have tried this when in pattern mode? sometimes it gives similar fx, it's cool