A Python module that will spit out a random 4–8 bar compound-meter rhythmic exercise in Lilypond code. Once I add more rhythmic options and make it generate the whole Lilypond score, I'll make a proper repo.

rhythmgen.py

# rhythmgen
# Python module for generating practice rhyhm exercises in Lilypond code

# usage:
# >>> from rhythmgen import *
# >>> randomLine(compoundBeats,randomCompoundTop(),randomBottom(),randomLength())
# then copy and paste the code into a Lilypond file with a percussion staff

# Copyright (C) 2013 Kris P. Shaffer

# This program is free software: you can redistribute it and/or modify
# it under the terms of the GNU General Public License as published by
# the Free Software Foundation, either version 3 of the License, or
# (at your option) any later version.

# This program is distributed in the hope that it will be useful,
# but WITHOUT ANY WARRANTY; without even the implied warranty of
# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
# GNU General Public License for more details.

# You should have received a copy of the GNU General Public License
# along with this program.  If not, see <http://www.gnu.org/licenses/>.

import random

def meter(top):
    if top == 6 or top == 9 or top == 12:
        meter = 1
    elif top == 2 or top == 3 or top == 4:
        meter = 0
    else:
        meter = ''
    return meter 

class Note(object):
    def __init__(self,duration,top,bottom):
        self.duration = duration
        self.top = top
        self.bottom = bottom
        self.meter = meter(self.top)        
    def lp(self):
        output = 'c'       
        if self.meter == 0:
            if self.duration == 'beat':
                output += str(self.bottom) + ' '
            if self.duration == 'div':
                output += str(self.bottom * 2) + ' '
            if self.duration == 'sub':
                output += str(self.bottom * 4) + ' '
            if self.duration == 'twobeat':
                output += str(self.bottom / 2) + ' '
            if self.duration == 'beat~':
                output += str(self.bottom) + '~ '
            if self.duration == 'div~':
                output += str(self.bottom * 2) + '~ '
            if self.duration == 'sub~':
                output += str(self.bottom * 4) + '~ '
            if self.duration == 'twobeat~':
                output += str(self.bottom / 2) + '~ '
            if self.duration == 'beat.':
                output += str(self.bottom) + '. '
            if self.duration == 'div.':
                output += str(self.bottom * 2) + '. '
            if self.duration == 'sub.':
                output += str(self.bottom * 4) + '. '
            if self.duration == 'twobeat.':
                output += str(self.bottom / 2) + '. '
        if self.meter == 1:
            if self.duration == 'beat':
                output += str(self.bottom / 2) + '. '
            if self.duration == 'div':
                output += str(self.bottom) + ' '
            if self.duration == 'twodiv':
                output += str(self.bottom /2) + ' '
            if self.duration == 'sub':
                output += str(self.bottom * 2) + ' '
            if self.duration == 'twobeat':
                output += str(self.bottom / 4) + '. '
            if self.duration == 'beat~':
                output += str(self.bottom / 2) + '.~ '
            if self.duration == 'div~':
                output += str(self.bottom) + '~ '
            if self.duration == 'sub~':
                output += str(self.bottom * 2) + '~ '
            if self.duration == 'twobeat~':
                output += str(self.bottom / 4) + '.~ '
            if self.duration == 'div.':
                output += str(self.bottom) + '. '
            if self.duration == 'sub.':
                output += str(self.bottom * 2) + '. '
        return output
        
def bottom():
    return int(random.sample([ 4, 8, 16 ],1)[0])

def lpCode(line,top,bottom):
    result = '\time ' + str(top) + '/' + str(bottom) + ' '
    for n in line:
        result += Note(n,top,bottom).lp()
    return result
    
compoundBeats = [ \
['beat'], \
['beat'], \
['beat'], \
['beat'], \
['beat'], \
['twodiv', 'div'], ['div', 'twodiv'], ['div.', 'div.'], \
['twodiv', 'div'], ['div', 'twodiv'], \
['twodiv', 'div'], ['div', 'twodiv'], \
['div', 'div', 'div'], ['twodiv', 'sub', 'sub'], ['div.', 'sub', 'div'], ['div', 'sub', 'div.'], ['sub', 'sub', 'twodiv'], ['div', 'div.', 'sub'], \
['div', 'div', 'sub', 'sub'], ['div', 'sub', 'sub', 'div'], ['sub', 'sub', 'div', 'div'], ['div.', 'sub', 'sub', 'sub'], ['sub', 'div', 'div', 'sub'], \
['div', 'sub', 'sub', 'sub', 'sub'], ['sub', 'sub', 'div', 'sub', 'sub'], ['sub', 'sub', 'sub', 'sub', 'div'], \
['sub', 'sub', 'sub', 'sub', 'sub', 'sub'], \
['sub', 'sub', 'sub', 'sub', 'sub', 'sub']
]

def randomLine(beats,top,bottom,bars):
    line = []
    if top == 2 or top == 3 or top == 4:
        card = top
    elif top == 6 or top == 9 or top == 12:
        card = int(top / 3)
    length = card * bars
    i = 0
    while i != length:
        beat = random.sample(beats,1)[0]
        for n in beat:
            line.append(n)
        i += 1
    return lpCode(line,top,bottom)
    
def randomCompoundTop():
    return int(random.sample([6,9,12],1)[0])
    
def randomBottom():
    return int(random.sample([4,4,8,8,8,16],1)[0])

def randomLength():
    return int(random.sample([4,5,6,7,8],1)[0])