I recommend you give the players a Bag of Beans. Its a chaos machine and a great method to get your players to do something fun without completely derailing the campaign. We all really enjoy the pink toads (random monsters) since you can just roll up something crazy and do a combat.

We had the mummy lord come up which ended up being a huge plot point after they let it sit for a while. It changed the course of what we wanted to play in a fun way.