I like the idea, OP. I've been a part of this forum for almost 4 years. A few threads come to mind.
1.) The infamous valet story - an M3post member had his car stolen at a Las Vegas hotel from the valet, and found it in a ditch later that day.
2.) M3post member in Florida who passed away. I hesitate to bring this up, but it was a sobering moment for all of us, and reminded us all of the caution we must employ when we drive our vehicles. RIP
3.) The M3post member who chased after a speeding M3 in his hearse (SchnellM3?). I have not laughed that hard in years. See post #5. (http://www.m3post.com/forums/showthread.php?t=640191
4.) All of the "is this a normal sound" threads. For example, the fellow who asked why his engine makes a loud revving sound when it changes down a gear.
5.) A shameless plug about my own little event, which was hilarious in its own way. (http://www.m3post.com/forums/showthread.php?t=560095