Older son asked for help to get him started on an English assignment last night. His class had studied Old English riddles and they were to go home and write their own. We talked about it for a while and this is what he came up with:

I am dry as a bone and wet like a fish.
I am solid as a brick,
But I wriggle like a worm.
I am cold then hot.
I am both ancient and modern.
I am loved by nerds and college students.
What am I?

Answer is in the comments.