How to ruin a Saturday, or what not to do to your bike

My rear wheel on my favorite wheelset has kinda felt weird for a few days. The breaking modulated a bit and I have been commuting on it through the horrible potholed streets of Bayshore, so I assumed I was in need of a true. So this morning I pull off the wheel, put it in the truing stand and give it a spin. Wow is it off! Then I see why. There isn't 1 crack in the rim, but 3! 3 cracks!? How the fuck did I crack my favorite rear rim in 3 places and not remember?!
I have had this wheelset for at least 10 years. Its a matching set of early 90's Mavic 501 hubs with Mavic MA40 hoops. It has been halfway around the world with me. I think it needed to be trued twice before. Did I mention it's my favorite wheelset?
So, if anyone stumbles upon either a 32 spoke Mavic MA40 rim or a pair of Mavic rims the same vintage (tubular or clincher) I am in need.