Your map is the greatest thing I've ever seen! I've always wanted to do a corkboard map, but I was just going to use regular old push pins. The lapel pins idea is genius!
I would love to find the time to put something together for my kids of all the parks we have been to. I originally thought I would get a logo baseball from each park but decided quickly after just 8 ballcubes that it would be too much to display if I ever got to all 30. A binder is a great idea and I could just use plastic page of different sizes I can get at the photo store.
Like most of you, I keep the stub or the printout (boo) for each of us for each game. I like to get at least one picture of us together with the field in the background and also some photos from my seat of the plate, scoreboard and showing as much of the park as possible. I try to get some exterior photos showing the marquee, entrance and any unique exterior features or statues. One of these days I'll find the time to have prints made!
For my ticket stubs, I place them in six-pocket sheets that you can get at baseball card stores or online. I place tickets in the bottom three slots and place the pocket schedule for that particular game above the ticket. These are then placed in a ring binder. For the "print at home" tickets, I place those in plastic sheet protectors. I also have albums full of stadium photos separated by league (majors, eastern league, pacific coast league, etc.) and I often take the box score or news story and put that in a photo page and place that with the stadium photos. Problem for me living in Arkansas, unless it is the Cardinals, the local paper doesn't put in box scores.
Besides the ticket stubs and pocket schedules, I also collect programs for each game and a cap for the home team. Related to Meg's suggestion for placing pins for each of the teams on a map next to the city, I have bought laminated maps at book stores (i.e., Barnes and Noble) and pin them onto cork bulletin boards that I get at Wal-mart. Not quite as nice as Meg's, but works nicely for displaying my sports pins.
Mark - I guarantee your maps and pins are equal to mine because they represent YOUR memories and that is what is important.
That's a pretty awesome idea Meg, but I bet that after 150+ parks your map has started to get juuuuust a bit cluttered at least a little I would think as some stadiums are in close proximity lol. I personally stick with baseballs but for minor league parks if I end up seeing a whole bunch it might not be feasible.