If you're normally a close up magician, then what would be wrong with using your repertoire? Just know how to routine it well.
EDIT
It's also a matter of presentation and how to make it play bigger for the entire audience. I saw this clip yesterday of Joshua Jay and there's a lot to be learned about how he handled the situation. http://www.youtube.com/watch?v=I5C3HSYAeh8
-Try and use many volunteers from different parts of the audience:
Ex. The biddle trick
- Give cards for inspection at left hand side of the audience, then get the
person to fully shout out the cards are real and not gimmicked then
spread deck for everyone to see
- Make a spectator pick a card in the middle (this is best because
it is in the middle and everyone would see it equally.
-Do the sleight of hand to everyone and possible up a step from the
audience.
-Do the final climax at the right hand of the audience then slowly move
from the right side to the left showing one is face down.
-get the spectator that picked the card to take it and show it to everyone
Those are my actual notes for when performing for a 20-25 p. audience.
Make your own notes for every trick you are going to perform, and practice
20 to 40 people are going to be quite spread out, so think more parlour/small cabaret than close up table stuff.
Ring on string, or any rope stuff would be good. Professors nightmare, cut and restored etc.
Cups and Balls or Chop cup?
If you do some card tricks, do stuff like card to wallet/shoe etc. As you can tell what's happening quite easily from some distance away. ACR probably wouldn't play to well as the action all happens in a very small close up area. Plus certain thngs like card to mouth only really work right up close.
Cards across?
If you want to do some Theory 11 type stuff, then Thread will work, and Gyspy thread.