Free GM Resource: A Free HM4/OSR Adventure...but Only for One Day!
Since it is written for 4th Edition it should run just fine for AD&D and most of the Old-School clones. Sure, some stuff might not make perfect sense (like use of the HackMaster Combat Wheel), but I would be more than surprised if an experienced OSR GM couldn't adjudicate on the fly. Just don't forget that in HackMaster everybody got a 20 HP "kicker" and the damage dice penetrated!
Please feel free to use this link (or click on the adventure pic) for the special deal and pass as many copies of said link to your gaming buddies, but be warned that it will only work for Monday, June 22nd.....whenever the DriveThruRPG servers deem it to be that date.
If I can ever find the follow-on adventure I'll get that on DriveThruRPG, but that adventure is quite silly (and stupid) and isn't really required at all.