I've been watching half hour segments of the old Johnny Carson Tonight Show that are shown at 2:30 a.m. each morning on MyKy. The other night he had Carl Sagan and Carl and Johnny remembered a limerick dealing with Einstein and his relativity theory. I thought it delightful. Apparently the original was written by A. H. Reginald Buller in 1923 or something. I have fiddled with it a bit.
A lovely young lady named Bright
Could travel far faster than light.
She set out one day
In a relative way
And returned the preceding night.
or
There was a young lady named Bright
Whose speed was far faster than light.
She set out one day
In a relative way
And returned the previous night.
According to Wikapedia there are other versions with slight variations, but they are pretty certain about the original author.