Alliteration: the occurrence of the same letter or sound at the beginning of adjacent or closely connected words.

Say a made up alliterated sentence from the last letter of the last sentence. I'll start.

Since my sentence ends with k, the next person's alliterated sentence will have the letter K. :P

Seven squinting sharks seeking seashells sink

King Kate killed Kat

Taco Tuesday To Taco Thursday

Yelling Yum Yay

You yawned yesterday, you yoghurt yard!