D.C. is usually counted as a state in discussion of Presidential elections since it was alotted electors under the 23rd Amendment. (This actually comports with a common practice in federal statute law where any of the federal territories that are treated equal to a state in the particular law are simply lumped into the law’s particular definition of “state”, which is then used to refer to actual stated plus the equivalent-to-state territories in the context of that law.)

Likely 'paulddraper is using 24 to mean 23 states + DC:

https://en.wikipedia.org/wiki/United_States_presidential_ele...

(The election even included a faithless elector, something you don't see every day.)

Indeed. It was a vote by a Republican for the Libertarian nomination.

It was also notable for being the first electoral vote for a ticket with a woman.