I don't know if this has been done somewhere, but it's a twist on the alphabet word thread.
1. Each word has to begin with the same letter that the previous word ended with.
2. Each word must build upon the previous words to make a coherent sentence in English.
3. Anyone who completes a sentence should type the entire sentence and provide appropriate punctuation
4. The first word of the next sentence must begin with the letter that ended the previous sentence. Sentences don't necessarily need to build into a coherent paragraph, but wouldn't that be even more challenging