Following our special Halloween patch Thery Scary we have a similar sample playback patch: Beats and Pieces. They are both available from the patches page. These patches are similar in that they both use the Aux button on the Organelle to play a sound file in the background. While the sound is playing you can play other sounds on top of it using the keyboard. In Thery Scary you control a Theremin sounding synthesizer, and in Beats and Pieces you play shorter sound samples. All of these sounds are in the patch folder and may be replaced with your own.
There has been a lot of interest in using the Organelle to play back samples, and Beats and Pieces makes a good example of this facility. In Pure Data (the programming environment used to create patches for the Organelle) there are two methods for playing sound files: streaming them from the disk, and loading them into memory (RAM). Streaming from disk allows you to play files of arbitrary length; you are limited only by the available space on the USB drive. Loading files into RAM allows for much more drastic playback manipulations in Pure Data, but there are limits to how long the sounds can be. Beats and Pieces uses both methods: it streams the background sound from disk, and loads the key sounds into RAM. So the background sound can be as long as you want, but the sounds for each key should be shorter (up to around a minute should be fine)