Help! We're Being Invaded by Tree Frogs!!

How do tree frogs get into a house? I suppose if I could answer that question-they wouldn't be getting into ours! Today when I came home from work, I walked in on one sitting on the toilet seat! With the light off and a quick glance, I thought one of the boys put something there to look like a little blob of you know what.

I went outside asking who had been using my bathroom while I was at work, and neither would admit it. I finally got Eric to come and take a look...with the light turned on and a closer look, it was definitely not what I thought it was-LOL!

Since Adam has been the resident frog catcher this summer (this is our third one in the house-one climbing the glass in our door wall in the dining room, the second one plopped on Adam's foot in the middle of the night from his ceiling fan and now this one), he very graciously removed it and put it outside. 

This is what it looked like...

 Photo borrowed from Michigan Herps-an Online Guide to Michigan's Reptiles & Amphibians

Any ideas about how they are getting in? Or where they are coming from? Or how to get rid of them?