Although not a winner for this post, some odd ones that I remember are:

mainline United service between Chicago-Monterey, California and Fresno-Denver.

TWA Wichita-Seattle (of course, there's the Boeing connection with large sections of the 737 built in Wichita then shipped to the Seattle area)

KLM Amsterdam-East Berlin

TAT/Air France Fokker 28 service London Heathrow to Lille then Strasbourg
Also Lille-Strasbourg-Milan Linate

Lan Chile Santiago-Easter Island-Tahiti (but people in South America would fly this and then take UTA French Airlines to Australia and there was no Qantas or Lan Chile SYD-SCL)

Delta Portland-Hong Kong (not that unusual)

Great Plains Dornier 328 Jet from Oklahoma City to Nashville? Great Plains didn't have much of a hub.

Western Pacific's Colorado Springs hub

PSA Concord (SF Bay Area) to LAX

Frontier Salina-Manhattan-Kansas City on a 737