Apart from cleaning your teeth (obviously) dental floss can be used for a number of other things.
Sew on a button: If you have buttons that re constantly falling off, sew it back on with dental floss. The floss will not slip and it is much stronger than ordinary thread.
Hanging/displaying things: Even though it is fine, dental floss is remarkably strong. Use it to hang pictures, wind chimes; you can even use it as a clothesline!
Separate things: When photographs get stuck together, gently pull a length of floss between them and move it gently from side to side to side. When biscuits are stuck to the tray, hold a piece of floss with one end in each hand, keep it tight and gently pull it underneath the biscuit and move it from side to side.
Cut the cake: Or the cheese! Hold a piece of floss in your hand making sure that it is taut. Slice the cake, moving the floss gently from side to side as you cut. You can also cut cheese in the same way.
Sew up holes: in heavy duty things like umbrellas and tents, you can sometimes get small holes due to wear and tear, sew them up with floss and they will last much longer, ordinary thread will not be strong enough.
Remove stuck jewellery: If you have a ring stuck on your finger wind a length of floss from the ring to your nail, make sure it is tight, you should then be able to simply slip the ring off the floss.