Mibuild (Milkymist Build system)
  a build system and board database for Migen-based FPGA designs

Quick intro:

from migen.fhdl.std import *
from mibuild.platforms import m1
plat = m1.Platform()
led = plat.request("user_led")
m = Module()
counter = Signal(26)
m.comb += led.eq(counter[25])
m.sync += counter.eq(counter + 1)
plat.build_cmdline(m)

Code repository:
https://github.com/milkymist/mibuild
Migen:
https://github.com/milkymist/migen
Experimental version of the Milkymist SoC based on Migen:
https://github.com/milkymist/milkymist-ng

Mibuild is designed for Python 3.3.

Send questions, comments and patches to devel [AT] lists.milkymist.org
Description files for new boards welcome.
We are also on IRC: #milkymist on the Freenode network.