Jaanus Kalde made this 32 channel light dimmer project, that is available at Github:
I needed a computer controllable 32 channel light dimmer for an art installation. After looking around a bit I found out that there isn’t even a Arduino shield for the work. So I made a quick 4 channel stackable board to control lights. The board uses SHARP thyristor based solid state relays to switch mains voltage. As normal with thyristors – all the outputs can be used as dimmers through zero-crossing detection. All outputs are able to handle 0.9 A / 200 W. We connected 40 W incandescent light bulbs to it but you can control whatever with it – lights, electronics, computers, motors etc.
32 channel mains lamp controller – [Link]