More than you can shake a stick at
Sinko de mayo
An ambulance because that is a serious medical emergency that requires immediate attention.
El Nio
Because he knows where the naughty girls live. (a kid told me this one)
Boy: Because he read the label and it said 'shake well before using.'
A nervous wreck! I first heard this at xmas 1952 (64 years ago) and it still makes me smile.
A switch hitter.
Because they needed a switch-hitter.