Marcus Padrini, from MusicApps, posted an excellent live jam. He even includes a custom preset for Geo Synth, link below.

Video Description:

Here is a JAM playing with just one iPad running GarageBand and Geo Synthesizer, with the support of Yamaha's P95 Digital Piano and iRig MIDI. Everything was made live. A little drum loop on SmartDrums, a GB Pad called moonrise and my Lead, released with Geo Synth (Padrini Lead), with some modifications (delay, cutoff and gain).

The custom lead can be downloaded here:
https://dl.dropbox.com/u/13574893/Padrini%20Lead%20LP%20MA%20delay%202.geosynth (Right-Click to Save As)

Buy Garageband on iTunes: $4.99

Buy Geo Synth on iTunes: $9.99