I recently changed my training tires for something a little more up to the challenge of not melting on roadways in 105 degree heat, and found a long-forgotten surprise waiting for me.
A used Gu wrapper inside the tire bead that I permanently "installed" when a piece of quartz wanted at my tube so desperately it ripped right through the tire. This wrapper has lasted through several subsequent flats (due to sharp objects in other sections of the tire). Paper money work equally well - a one-dollar bill has been a linchpin in one of my rim-strips since June 2008(!) and it's still going strong - but I remember I didn't have any singles on me at the time.
Now you know what really holds the ship together on a daily basis.