I have something in the quiver

What an ABSOLUTE load of b***sh*t, absolutely no such thing in English!

Certainly goes to show you cannot believe everything you read on here.

#2 take a chill pill!

in their repertoire.

könnte im richtigen Kontext auch passen.

@5 - it's up their/my (etc) sleeve, not "the"

in their arsenal

Up their sleeve is sneaky.

up their sleeves, unless their all wearing the very same shirt. :-)

... die Metapher ist übrigens schief . . .

Man hat mehrere 'Pfeile im Koecher'

oder man hat 'noch etwas in der Hinterhand / in petto' . . .

Letzere übersetzen sich beide zu:

'to have sth. up one's sleeve = etw. in petto / in der Hinterhand haben' . . .

@9: Mehrere Pfeile im Köcher is, as you undoubtedly know, more strings to one's bow. You're right about the mixed metaphor.

@8: Interesting point. Would all children who know the answer please raise their hand(s)? Would hands here signal two hands per kid, or one hand each per many kids? With the sleeve(s) I would find the expression unremarkable in either singular or plural. Logically you're right. Would that English were as logical as you are.

for what it's worth:

sleeve - 1.3 million goggle hits
sleeves - 2.7 million

so it's basically 2:1 for the plural faction. :-)

@ Dude: I think I'd say "they have something up their sleeve" - idiomatic

"they have something up their sleeves" is of course logical but it's literal and the idiom's somehow gone '

but maybe it's just my feeling

I suppose it's a personal preference, but I don't agree that the plural would make the idiom disappear somehow. Look at these fairly authoritative sources:

http://www.nytimes.com/1993/06/09/garden/eati...
EATING WELL; Some Pros With Low-Fat Dessert Tricks Up Their Sleeves

http://www.encyclopedia.com/doc/1G1-96892260.html
Wheel 'n' deal: auto salespeople have lots of tricks up their sleeves to get you to pay more, but you can beat them at their own game.

http://www.canada.com/edmontonjournal/news/sp...
Eskimos have more tricks up their sleeves

http://www.timesonline.co.uk/tol/sport/rugby_...
Leicester have more tricks up their sleeves

...like I said, maybe it's just me!

'in their roster' wäre vielleicht noch eine passende Variante...

support Mike - what Germans often forget and find highly illogical is that we often use "their" not just as a plural ("sie" equivalent) but to mean HE/SHE without specifying a gender - hence the possibility of the singular after "their"