Some specifics:
"Prom" from When it Rains Gasoline (can be taken seriously, or comedic due to exaggerations)
http://www.dramaticwriter.com/Alysa.html
"Bagels" from Funny girl (punny, no funny- warning, it rhymes!)
http://www.whysanity.net/monos/funnygirl2.html
"Queen" from You're a Good Man Charlie Brown
http://www.stageagent.com/Shows/MonologuesView/1057
"Don't Let me Be Normal" from the Fantasticks
http://www.stageagent.com/Shows/MonologuesView/1014
Some other places to look:
http://www.whysanity.net/monos/female.html
http://www.stageagent.com/Shows/monologues
http://www.monologues4kids.com/dramatic-monologues-for-kids