I'm about to sign up for my quadrennial Ironman. I've raced 2007 IML, 2011 IMSG (the now defunct St. George full), and 2015 IMLP. I planning to sign up for Chattanooga next week and don't see a common abbreviation for this event. I already sick of typing out Chattanooga. Every IM needs a standard abbreviation so I'll propose them here for everyone to agree upon and use moving forward. I'm only going to list the North American races because, due to costs and logistics, those are the only races I really consider. I'm sure the other international IM's are great races, but I'll leave them for others to figure out. And I'm not even going to consider the 70.3's. Those things are breeding like rabbits. We'll never keep up with those. Plus, they aren't real triathlons anyway. ;)

Texas - IMTX
Santa Rosa - IMSR
Boulder - IMBO... :)
Lake Placid - IMLP
Canada - IMCA
Mont-Tremblant - IMMT
Wisconsin - IMWI... or IMMOO, is there really that many cows on the course?
Maryland - IMMD
Chattanooga - IMCH... I've seen IMCHOO. Is this a play on IMMOO? Anyway, IMCHOO is too long.
Kona - KONA... This race doesn't need an abbreviation when used in these forums.
Louisville - IML
Florida - IMFL
Arizona - IMAZ
Cozumel - IMCZ