HELP!!!

I need your help! Im clueless when it comes to riddles. It seems my mother is doing a huge Halloween scavenger hunt for a group of troubled youth and came to me for help... She already has the format of the hunt down, and she tried to come up with riddles for each clue. The problem is that she is a first grade teacher and kinda brought that mentality into the riddles, this is a teenage/college age group. So long story short if anyone is good at riddles and you think you could help me make what she has harder PLEASE HELP! It would be a great thing for a good cause. Just let me know and ill give you more details.