Monica Geller is a character on Friends. (Played by Courtney Cox).
A former fat girl who overhears someone (Chandler Bing) refer to her as "your fat sister". After that she loses a lot of weight and becomes quite a hottie. She eventually moves to New York City and lives with Phoebe Buffet, but Phoebe can't stand living with her so she moves out. Later her high school friend Rachel moves in. Rachel stays until Chandler Bing (the same one who called her fat) gets engaged to her and moves in.
Monica is extremely competitive, extremely self-conscious and very much a neat freak. She doesn't have a lot of funny lines, instead she is put into a lot of funny situations caused by her own personality flaws. (Basically just like her brother Ross Gellar).
Monica and Chandler were married on the season finale of season 7. (Something that was delayed due to Mathew Perry's drug problems.)