Some time ago, the front plastic piece for the HVAC and radio on my yellow Fiero broke on the bottom where it is thin. I tired gluing it with JB Weld -- didn't hold. I tried gluing it with super glue -- didn't hold. I tried bridging the break with a piece of plastic held by super glue -- the bridge broke.
So now I have tried something new, called LazerBond. It remains a syrup-like liquid until hardened by UV light. This is the same thing as another product called Bondic, which was discussed on Pennock's, but costs less than half as much. So far it's holding -- I'll let you know later if it breaks.
Click here to learn more about this stuff, and see a cool video about it.
Edit to add: If you have to work outside with this stuff, keep the dispenser and your work in the shade. There's enough UV in sunlight to start the hardening process. I had to scrape some hardened stuff off the tip of the dispenser with my knife after exposure to sunlight.