PARK TOOL TOOLS
We have learned the hard way the things that do not substitute for a tire lever: Metal spoon, screwdriver, fingers, floor pump thumblock, prayer and much more. The humble tire lever, in this case the Park Tool TL-1 Set-of-3 Tire Levers, is something so simple yet so vital for happy & self-sufficient bike riding. They're good for helping you fix countless flats thanks to their durable nylon construction. They are tough to bend and even tougher to break, but likewise they peel back the bead of your clincher tire without doing a whit of damage to your rim. Don't leave them behind because if you do and you flat you are totally screwed.
The TL-1 is a 3-pack of levers. You can loan one and lose one because you really only need one to fix a flat. There are a few wheels out there (Campagnolo rims come to mind) where the tire fit is so tight you may need 2.