From a favorite client:

For the office dictionary 

Sunday return - noun, a term reserved for difficult client returns, clients who's tax situation changes every year and isn't ever the same twice. Must have a minimum of three K-1's, although two-for-one credit is available for K-1's restated after the return is finished, but not yet filed.  Bonus credit if one K-1 is from a PTP.   A similar term to used in the office is "Sunday Client", as in "The Smith's are Sunday Clients" as I'll be working on their return all day Sunday.  

Yep.. by now there aren't any easy returns.  Only 'less bad' returns.   BTW, I *hate* the month of March.