Generally I'd consider anything commonly used in the 50's as the basis for a potential melee weapon. Street signs, car axles with bits welded to the end...
For the battle axe crowd, howzabout a stop sign cut to an axe shape and sharpened? Or a length of piping cut at an angle would make an extremely effective spear considering it's hollow... sort of a very unintentional blood groove.
Instead of a morning star, think cinderblock-on-a-chain. Lawn mower blade already goes into the Shishkebab, but why not just wrap one end in leather for a machete?
Improvised weapons are dead easy to think up. Just figure out what's heavy, sharp, or easy to grip.