@ned pranks have to be really really carefully executed to be funny and not cruel.
Like, adding googly eyes on packages in stores - funny, and I'd count it as a prank more than anything else. Elaborate rickrolls (especially in non-computer settings like when Rick Astley jumped out of a Sesame Street parade float) - funny pranks.
Puns on the other hand, always fun and no risk of being hurtful.