This is not exactly tesla coil stuff but it is interesting and has to do with large sparks.
Saturday night we had another thunder storm and tornado warnings. Lightning struck the house. There is a 19" hole in the roofing shingles and plywood on the roof. Directly below the 19" hole is a 7" diameter hole in the sheet rock ceiling in the upstairs bedroom. The bedroom floor has a 28" diameter hole in it. Down stairs the 28" diameter hole is directly over the refrigerator. The refrigerator measures 30" x 33". Several of the circuit brakers in the main panel were tripped. The 36" TV in the living room is fried. There was no fire and not even a sign of anything burned. All the holes look like a shotgun blast made them. The wood around the edge of each hole is splintered like all the wood that is gone was ripped away. We were in the living room watching TV at the time when it happened it sounded like a stick of dynamite went off in the kitchen. The TV made some cracking sounds and went off. There was a large flash of light from the kitchen area that reflected through the house. There was also a strong smell of smoke like something had burned. The burned smell had to be the wood that was missing from the holes because there was very little wood pieces laying round to clean up. The Insurance Company is refusing to pay for the TV since it was in the living room 20 feet away it could not have been struck by lightning. Allstate is being a jerk, your not in good hands with Allstate. The variation in hole sizes is very interesting.