My most memorable is a rules screw up I made. Won't forget that again, I promise you that. And, IMO, it should be my most memorable.
As far as incidents, a coach who I had already ejected once in the year telling my "partner" after a close call at 2nd that went against his team to "watch your partner out there" without any response from the PU other than "ok, coach."
Signing off for 2007, with some humor below
Tuss