This link is to the original project for a square wave midi synth, which I based my synth on, and has the info you would need to put the midi together, although the pins are different in my current  version. See the previous post below. You just need the midi input circuit on a breadboard, and a midi jack, I cut one off of an old PC midi adapter. The Launchpad itself is $4.30 from Texas Instruments.
 http://forum.43oh.com/topic/364-launchpad-simple-midi-synth/

In A Tempermental Mood?

Better, really, but I do need to fix something after having cleaned up the code.

` More Lucy. Ignore the guy in the hat!

Low-Res Lucy PWM Synth code --Current Version of Code

Here is the current code. HW UART is used to read the midi data, and attack and LFO controls have been added, as well as an equal no. of Hz detune on osc3. Note that the pins have changed-- midi in is now 1.2 and out is 2.2.

https://www.box.com/s/gp84cvvn6eyckyyispdf

Here is an audio sample:

Lucy song

All Down The Line
This is the first real song I've done using Lucy (as well as other instruments). It now has hardware UART, which makes the midi in much more stable. A few enhancements and finishing touches and I'll post the new code for it!

Lucy PWM Synth demo -- code below

This is a demo of the 'Final' (for now) version. Can't really hear as much low end through the camcorder mic.

New Lucy PWM synth code-- 3 osc.

Lucy 'Final' code. Now I want to record some music with it!