I have not payed much attention to my own milestones. This was one I did plan out. The GPS Adventure Maze in Baltimore Maryland. If I get to 1K it probably will be a GRC or LPC.
The best part about the eclectic things I do is watching how big the eyes get and the little screams that come out of big burly cops, firemen, EMT's and other municipal officials. I tell them ghost stories, tails about geocaching, cemetery adventures and things like that all day and then driving down the road my Nuvi goes bing and I have to stop and run off into the bushes to find a cache. Most of the time I can't pry them out of the van after dark, but if I can get them to try it, once is about all I get.
As for ding things for the hobby, I don't really think I have done anything that special. I'm just really glad you all like the hides.