1. Use fanfiction.net's Search >> Story By Summary and look up your name in either Harry Potter or Lord of the Rings.
2. If there are any Mary Sues that share your name, pick the worst-sounding one and post the summary.
I didn't limit myself to HP and LotR, and I found horrors. Oh the horrors.
1) A Buffy/HP crossover:
X-over with HP. Rachel Grimm is the granddaughter of Buffy Summers, and is currently the Slayer. Her new Watcher, Naomi Tyson, is a little strange. When two wizarding worlds collide a new Hellmouth opens, and things get a little hectic. Chapter 4 up!
2) Buffy 'fic:
Rachel is a young girl. Then she is changed. The year is 1882. Then it is changed. Little memorys can make you wonder. My first fic, it's only getting started. Please r/r. [Bad spelling, bad grammer, dialogue shallow at best... On the plus side, the plot was at least a little interesting.]
...and I was afriad to look at any more. *shudder*