Librarians or library patrons: Suggestions for a "library party"

My boss has asked me to plan a “week of festivities” for National Library Week (April 12-19). I have a budget of about $200. This is a small academic library for students majoring mostly in legal or health fields.
Ohkaaayyyy… so far the only things I can come up with are food/refreshments and perhaps a scavenger hunt with some door prizes, but my creative gears aren’t turning. Any suggestions from anybody who’s done one of these things? (I’ve done them at much larger places with humanities emphases, but I’m trying to think of how to tailor it to a much smaller place with lots of non-trads and WIDELY diverse user group, so a public library might be a better model.)

How about a coustume party… Everyone comes dressed as their favorite literary character, with a prize for best/most creative, etc.

A library party? You’ve kept that quiet.

Since you specilize in law and medicine, how about a mock trial involving the medical field, maybe a malpractice type case.

Or I’ve heard a lot of great stuff about University 101 classes doing a “library mystery” scavenger hunt, where you find clues and stuff and solve the mystery. It always seemed really cool and fun to me.

You beat me to it. I have nothing.