Peasant Railgun
The Peasant Railgun, a weapon of mass game-breaking destruction.
Relies on a few basic rules in the DnD system: readying actions and the length of a combat round (6 seconds).
Creating a Peasant Railgun
1. Hire a ton of peasants; let's just say that it is two thousand two hundred and eighty. Line them up in single file; this will form a chain of peasants two miles long. It'd be four miles back in MY day (witness me hiking up my 2nd Edition suspenders).
2. Buy a ladder. Just buy a standard, ten-foot ladder. Disassemble the ladder into a bunch of rungs and a pair of mighty ten-foot wooden poles. Hand a pole to the peasant at the back of line.
3. First round of combat. Peasant at the front of line readies an action to throw the pole at the enemy. Every peasant behind him readies an action to hand the pole to the peasant in front of him.
4. Next round: peasants fire off their readied actions, passing the pole two miles down the line and hurling it in six seconds or less. Pole accelerates to the speed of 1200 miles per hour, or a little less than Mach 2 at sea level.
5. Peasant Railgun can be reloaded and fired in less than 12 seconds.
6. ????? - Really, your choice. Weapon is scalable, you could use your peasant railgun to fire a number of things at a really long range. Add more peasants to make the weapons even faster; paint them red to make them fasta. Use gobbos to make a DnD grot cannon. Hurl pointy bombs for HEAT weapons. Severed heads make an impressive psychological warfare tool. It's even more wild with a bag of holding - place a team of fighters in it for DYNAMIC ENTRY over castle walls and shit, hurl some fucking bear cavalry directly into enemy lines, who knows. You can also throw a halfling monk to take full advantage of Flurry of Blows at 1200 mph. Combine this with the 15,000,000 gold-a-day trick and you're ready to absolutely ruin your DM's day.
7. Motherfucking PROFIT
Practical Applications
A campaign I was in recently employed a peasant railgun in a large-scale battle. Our mage was a dumbass and decided to launch an alchemical flask from said railgun and into the heart of the enemy forces. It blew up and killed a bunch of the enemy. Our DM got back at us by making it tear a big-ass hole in the time-space continuum. The same mage decides to approach the hole, and when he touches it, it blasts him across the fucking map and vaporizes some more enemy troops.
Warning
If your DM is paying attention, the projectile just falls harmlessly to the ground at the end of the chain, because there's no rules for acceleration or momentum in D&D.