They go off on tangents.
Anyone can roast beef, but not everyone can pea soup. (As told by my 8yo, who made me laugh with a joke for the first time. Proud dad moment.)
Cheese Was! some old guy came up to me on the street and told me this one.
because she couldn't control her pupils
He brought it to school and said 'An Ape-lle for the teacher!'
Americans don't get them.
I know plenty of raunchy jokes, but was asked this recently and came up blank
Angles in the Outfield
You always end up going off onto tangents.
A tangent