How I Did It
Uses samples from:
Tools I Used
LMMS, SoundFont plugin, ZynAddSubFX, C*Plate2x2
Samples I Used
crash02.ogg (included with LMMS) - Presumably royalty-free
FluidR3 GM - LGPL v2.0 or later (I think)
tgsf21x (http://www.sf2midi.com/soundfonts/file-detail/tgsf21x-sf2-3914.html or http://soundfonts.darkesword.com/fonts/tgsf21x.sfpack) - Not clear on the licensing.