Obscure Names in Mathematics I recently stumbled over the "Happy Ending Problem" (cf e.g. http://en.wikipedia.org/wiki/Happy_Ending_problem), which made we wonder, if there are other conjectures, theorems or problems, whose names do not give any indication to what they are about or, to which person it is related;
the "kissing number" would not qualify here, because it is a definition, but neither a problem nor a theorem.  
Besides the "Happy Ending Theorem", I also found  


*

*the "No-Ghost Theorem" (cf e.g. http://en.wikipedia.org/wiki/Goddard%E2%80%93Thorn_theorem) in the context of "Monstrous Moonshine".

*the "Mother Worm Problem" (cf e.g. http://citation.allacademic.com/meta/p_mla_apa_research_citation/2/0/7/8/9/p207895_index.html?phpsessid=a0a1836d9b5ca905a3cff4af0fa64752)  

*the "Dining Philosophers Problem" (cf e.g. http://en.wikipedia.org/wiki/Dining_philosophers_problem)
 A: The Busy Beaver Problem.
The Beer Glass Theorem.
The Garden of Eden Theorem.
A: Pigeonhole (or Box) Principle.  (Note that "rational box problem" is very different from "Box principle".)
Jugendtraum (as with Dirichlet for the Pigeonhole Principle, 
 the name of Kronecker is sometimes omitted).
A: Hauptvermutung
Technically this is a conjecture, but there are results about whether it is true or not under various circumstances.
A: Tropical geometry
Margulis napkin problem
Traveling salesman problem
Canadian traveller problem
A: The master theorem. ${}{}{}{}{}{}{}{}{}$
A: I'm not sure if all these give "no clue", but they are somewhat obscure clues:
The Law of the Unconscious Statistician.
The Chinese Postman Problem
The Googol Game (aka the Secretary Problem)
The Butterfly Lemma and The Snake Lemma
The Art Gallery Theorem (or Problem)
and for those who know some Latin:
Theorema Egregium and Pons Asinorum
A: The Ham Sandwich Theorem. 
The Hungarian Method. 
The Hairy Ball Theorem. 
The Konigsberg Bridge Problem. 
The St. Petersburg Paradox. 
The Futurama Theorem. 
A: The Ten Martini Problem was a conjecture posed by Kac and Simon and answered by Avila and Jitomirskaya.
A: The Killing-Hopf theorem (yes, Hopf is already dead).
The ugly duckling theorem.
The no free lunch theorem.
The Cox-Zucker machine. 
A: For a theorem whose name is actually misleading about its actual content, check out the case of the Diversity trumps ability theorem, as described by Abigail Thompson in a recent Notices: http://www.ams.org/notices/201409/index.html
A: The Hauptsatz (due to Gentzen). 
A: The Stable marriage problem. $ $
