I'm not sure if this is availble anymore, but Craig Snader put on a book on Magic Squares in the early 80s. It had two levels of entertainment. First, you could make a square for ANY number called, positive or negative. Second, you had each square on the board (4x4) headed with letters of the alphabet. You then sat, blind-folded if you wished, and had spectators call the letters out randomly. When each letter was called, you called out the number to be inserted. When finished, you had a sqaure for the target number.
My thoughts on Magic Sqaures are that they are good if put into a proper context. Rather than a "Look what I can do" idea, some kind of story to which the audience cna relate would enhance WHY you're doing it.
One idea I've had but never had the time (or guts?) to construct, is to fall into a trance and channel a dead mathematician or scientist Einstein, etc) and then do the square. This would be interspersed with pithy or dramatic monologue of their life and times.
Just a thought. But if you can track down the Snader book, it is a good resouce. Not quick and easy, however,.. It requires some memory work and quick calculation ability. But the results are pretty spectacular, Magic-square-wise.