Or as a way to spread some "happiness".
I occasionally do card tricks. I consider myself very amateur, but I've spread some happiness with them. I only know a few.
I go back and forth on this. Some folks think grown-ups doing card tricks is silly. Some just don't like card tricks (or sleight of hand of any kind, really). Some are all for it.
So I guess the question is this: How effective would card sleights be as an ice breaker?
I think it depends on the trick.
Though, card sleights are a good way to practice body language. The body language and "patter" that go along with sleights can help, too.