i've got a certain cat who decides if the litter box is clean enough for her. if not, she'll go outside of it. it's easy to clean up in the bathroom, but in my room i have carpet. what cleaner works in getting the smell out. and how can i stop her from going there again?

Soak the stain with a mixture of:

2 c hydrogen peroxide
2 t baking soda
2 drops liquid dish soap

Let sit 24 hours and blot up any remaining moisture. The smell will fade as it dries.