Ring that Bell
From A KoL Wiki

You enter a room occupied solely by a carnival barker standing next to a strength-test machine.
"Hey there, pally," he barks. "To pass this challenge, what you've gotta do is step right up and hit this here ball with this here n-pound mallet. Hit the ball, ring the bell, and win a kewpie doll for the little lady. Or, y'know, no kewpie doll, but I'll let you pass."
(Successful attempt)
You hoist the heavy hammer and hammer on the ball, ringing the bell just like playing a guitar.
"Nice work," barks the barker, as he steps aside to show you the stairs.
(Failed attempt)
You tug with all your might, but you can't even lift the mallet. Looks like you need to buff up a bit, son. Or daughter, as the case may be.
Occurs at Fernswarthy's Basement.
References
- The successful attempt text contains a play on Chuck Berry's song Johnny B. Goode, which tells of a country boy who could "play the guitar just like ringing a bell."