We've seen superior beings like Q and such like have near miraculous powers which can only be described as magic or is it technology? Remember Clarke's Law "A sufficiently advanced technology is indistinguishable from magic."
I have an idea involving the Faerie Veil (ie. the dimensional barrier between our universe and the world of Faerie (or Sidhe or Fey Folk)).
Anyway, the idea is that some sort of sub-space phenomenon has weakened the veil and Fey creatures start popping up all over. The problem is that their natural magic aura disrupts technology and as the veil weakens technology begins to break down as magic begins to enter into the Federation.
Obviously at the end of all this chaos, I'm sure one or two Fey would be left behind (there always is one isn't there) and well one of them may just join the crew...actually he would won't he? Anway, aside from just using psionics, does anyone have any ideas of how to simulate magic without spoiling the game balance.