As I read it, the legality had to do with the voice files not the programming around it.
There'd been a project to create It'sLenny on your own PBX.
I recently installed IncrediblePBX, and, without realizing that Lenny was unavailable, installed the script from nerdvittles.
Once that was done, the programming was in place (and I'm unsure whether it was the install from nerdvittles or the IncrtediblePBX that put them there).
Anyway, if you create voice files in your /var/lib/asterisk/sounds named Lenny01.ulaw through Lenny15.ulaw you will then have a working Lenny-with-your-voice at local/53669@from-internal.
I'm still figuring out what they should be, and how to record the sound of a phone being picked up. If you're on Windows, Audacity does a fine job producing ulaw files. My issue is that I don't channel Lenny very well. There was someone else here who mentioned having created ulaw files with his two sons (3 and 6 I think) asking "do you want to talk to Dad?" and "Daaaad! Are you coming?" (off phone) and "He says he's coming!". If I had little kids, I'd go with that, and maybe the older kid trying to get the phone away from the younger ("No! My talking! Hiiiiiii! How doing?" from the younger one).
Also, I'm pretty sure the actual It'sLenny voice files are on DSLReports somewhere, although IMO it's probably better not to because of the legality thing.