The local Elks Lodge janitor took an old (1950s) Brunswick table down (without consulting the regular players) and busted the center slate by letting it topple over.
Some chips broke out along the diagonal crack. One of the lodge members bought the table for $200. When he set it up, he added some 1/2" slats across the bottom wood to give horizontal stability, and mounted it on the frame. He then used a machinist level to level the two pieces to each other, then leveled to the other two pieces. Only when everything was perfectly aligned did he fill in the gaps with bondo.
He said, when the table is taken down next time, the whole process will have to be repeated.