When I was a kid my
Dad showed me this trick:
1) Take a
straight pin and poke it into a
banana at one of the dark lines that run down the length of the
fruit.
2) Carefully, without coming out through the other side of the peel, drag the point of the pin around the entire inside edge of the peel, completely severing the fruit.
3) Repeat as many times as you like, slicing the banana inside the peel.
4) Leave it in the
fruit bowl for the next
unsuspecting victim.
I'm not sure if the results are any different than those of
cinnacism's method, but this way you don't need a thread.