It really depends on the trick. Card tricks are hard to throw into a conversation. As people have said "hey that's interesting, now on a similar subject allow me to whip out my card deck and show you some card tricks" doesn't work very well!
Stuff like levitation on the other hand is gold. Last weekend I was sitting at a table in a bar with three girls, one of whom was talking to me about god knows what, i wasn't really listening. Anyway I was playing around with a £5 note and all of a sudden it just floated up in front of me out of my hands - the girl just trailed off and her jaw just hit the table! I couldn't have got rid of her and her friends for the rest of the evening if I had tried!
