This is the first time I have been wandering around looking at stuff in the very early stages.
This post has one of the first big lists that might be useful for people brainstorming stuff, even past LudumDare. http://ludumdare.com.../weapon-ideas-ldjam/
(Slightly edited by me)
Infectious Agent: a restaurant owner is trying to poison the right spy without killing customers.
Kite a Giant: lure a large monster toward a city/castle/friend’s cooler treehouse/etc
Sunlight Focused: kill a neighbor’s flowers with beams of concentrated sunlight
Food Fight: a cafeteria featuring students with ridiculous weapons, such as mashed potato guns and banana missiles.
Toys: inspired by the Robin Williams movie, in which wind-up toys fight (I recall this is a multi-decade old game already).
Information Warfare: choose which important papers to shred in order to leak secrets.
Books: check out books from a library before your coworker does to prevent him/her from getting that promotion.
Numbers vs Letters: it’s a battle between the higher level and abstract thoughts!
Shapes: an RTS inspired by the different shapes in Flatland.
Monopoly: use market pressures to defeat your competitors.
Avalanche/Cave-in: cause a disaster to trap other people.
Cactus vs Balloon: inspired by some art in my room.
Nanotechnology: tiny invaders that destroy your enemies from the inside out.
Mind Control: make your opponents do self-destructive things.
Fear: scare people towards disaster (for them, obviously).
Vampire Hunter: use blood disease to kill vampires.
Eggs: birds hatch and peck at opponents.
Plunger: you’re a plumber, and you have to save the day.
Hopes, Dreams, Aspirations, and Fears: you work in HR at Large Corporation, Inc.
I also tried to come up with a list of potential weapons:
Summon beings, such as demons
Ever increasing mass
Laundry (dirty or otherwise)