The first thing which happend to me was to my favorite game at the time, a computer version of The Game Of Life (I know, I know, but I was only 5 or 6, ok?). My little sister put it into the disc drive wrong, closed it, and it got crunched into millions of pieces (Or at least it SEEMED like millions to my devastated little mind). Another thing that happend was when we updated from ethier Windows 98 or ME to XP, my copies of the computer versions of Monopoly Jr. and Tonka Raceway (Again, I was 5 or 6) both had no compatibilty with Windows XP. Most recently, my copy of Pokemon FireRed, on which I had a level 100 Charizard, a level 80 Zapdos, and others, completely stopped working on me. After doing a little research, I found out my copy was FAKE! (Dang you China!)
EDIT: Really, Forumotion? You put shopping links on Win 98 and Monopoly Jr? Wow...
EDIT 2: After editing, the links disappeared, but they will likely be back.