You must Google "nature sounds" and click on "Free Nature Sounds Mixer"
I am loving this because I can listen to rain on the roof with grasshoppers, sheep and wolves in the background while I type my profound philosophy papers. And on top of that one could even listen to Darth Vader and cats purring in the background so it really fits any mood your in. I personally like the rain on the roof with the thunder turned all the way up.
Well have a good day and may the Holy Spirit be with you.