This seems fun: can you cast shillelagh on a lit torch?
As a lit tourch isn't a club or a Quaterstaff, then no. ;)
Edit: A Club (Simple Melee Weapon, 1sp, 2lb) also isn't an unlight Torch (Adventuring Gear, 1cp, 1lb).
Technically no because it must be cast on a club or staff and a torch is neither. But i'd totally allow it at my tables.
It wouldn't be hard to turn a club into a torch, just wrap the end in cloth and dip it in pitch. 
With Produce Flame and Shillelagh, you could have a flaming magic weapon whenever you wanted!
Direach wrote:
Veleria wrote:
I think I would allow it once per torch, but I am not sure how many hits before the "club" is too damaged by the fire to be a club anymore......
I think it's fine to RP it that way, but don't expect to do fire damage with it.
crabcrouton wrote:
Direach wrote:
I would say that it would be cool to light up you Shellelgh staff, and that it burns for duration.
Also you could end the spell by regullar ranged spell attack, or you could discharge it after succesfull melee attack.
with one action to cast Shillelagh, one action for produce flame and one action for melee attack, i don't see nothing wrong with 2d8+wis damage with one attack.
It was definitely meant as more of a fun, one-time thing than an ongoing combat tactic. Might be helpful fighting something that would be scared of fire, like normal animals or, uh, a snow golem. Anyone else find unusual potential uses for simple spells?