We on the Dope have our own weird little collection going:
2-1/2 years, 3300 posts about custom license plate spotting. What are we thinking? 
And it’s not even the first thread on this topic. But definitely the one with the most staying power.
Interestingly, the ancient threads died quickly. The last-decade’s threads lasted awhile before petering out. This one will probably live for the rest of the board’s lifetime. Is the difference that custom plates are more common now or that we’ve turned into boring geezers with little else to occupy our minds or days?