ORIGINAL: squeaky penguin
It's an almost new NGK. I put it in right before I made the first two flights with the engine, and that's all its been run. Also, the ignition battery is fully charged, so that's not the problem either. The ignition seems to be the only thing left.
How many volts is your ignition battery? Did you test it by putting a load on it? NiMh and NiCd batteries sometimes seem to be charged fine while in fact they aren't. Do you have any ignition cut-off and/or a switch between the battery and the ignition? You might wanna try to bypass these and see if the plug sparks fine.
If all this doesn't help you, the ignition is probably RIP. Also keep in mind that a fully charged 5-cell NiMh or NiCd battery can damage the ignition module.