62150 Paragraph Changer

Would like a php script that would allow me to paste in a paragraph, and then click submit and it would search the paragraph and replace random words with new ones. See example below. Say I put in the following: My name is Bob and I like to run far. I like to run far because running is exciting. Your program should have a generate button that can be clicked over and over. And would perhaps on the first 2 generates generate the following output. 1) My name is Bob and I love to run long. I enjoy to run long because running is fun. 2) I like to run far because running is great. My name is Bob and I like to run far. ============================================ If you already know of software or a website that does this online I am even willing to pay for the information. I prefer speed. Please do NOT re-invent the wheel just teach me where it is =D