V---2nd. Chap 13 still "What is your act, ace?"

[Mark Kohut]

Benny snaps at Stencil. p. 385 hc

"Paola loves you, Profane." 
"You think that impresses me? What is your act, ace? 

"Ace" is an ironic slap, here, yes?  ("Young Stencil sighed".)

Lots of use of 'ace' in AtD.....
 
From wikipedia on Ace:
it traditionally meant 'bad luck' in Middle English, but as the ace is often the 
highest playing card, its meaning has since changed to mean 'high-quality, 
excellence'. This connotation has seen the word applied to a.... a person 
proficient in their field, especially a sporting field.
Historically, the ace had the lowest value and this still holds in many popular 
European games..... However, in most games popular in the English-speaking 
world, aces have the highest value of all cards in a suit. Many games, such as 
poker and blackjack, allow the player to choose whether the ace is used as a 
high or low card. 

The folk tradition of "ace high" existed in some games as of the late 15th 
century, The promotion of the ace symbolised the removal of the nobility 
(especially King Louis XVI) and the promotion of the common man. 

 
I think TRP has Benny call him 'excellent' [in his sporting field]...but Benny 
spits out the bad luckness [to him] of it at the same time.