I recommend MilkyTracker, from www.milkytracker.net , the program is very simple, it's basically load samples and play them back at different frequencies. You can even draw small waves into the sample editor, and create chip-like noises (the next version coming soon will have waveform generation and mixing, which I'm looking forward to), and you can tweak instrument envelope settings etc. in the instrument editor.
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Aspies: Because great minds think alone.