Long ago, when the internet was relatively new, I ran across a list called, "The Greatest Things About D&D."
Only one item on the list stuck in my head to this day: "Having to calculate the trajectory of a thrown goblin."
I've never actually had anyone try to throw another creature since about year 2000, when I was still in 2e. It's never come up, so I've never considered the d20 rules for such an attempt...until now.
I've got a player in one of my games who just made a character who could very well have the ability (and motivation) to throw people. He bugged me for rules on how this would work, so I had to oblige.
Here is a new house rule for throwing creatures.
"Creatures are considered two handed improvised melee weapons for the purposes of throwing them. This means you must use two hands as a full round action to throw them. Tiny and Diminuitive creatures have a range increment of 10ft. Small and medium creatures have a range increment of 5ft.
If targeting a specific floor square, treat the creature as a splash weapon for determining the result of the throw. The AC is typically 5 for a segment of floor, and the directional rules for a miss also apply. If targeting another creature with the throw, a ranged touch attack is required.
Damage from being thrown - A thrown creature is dealt falling damage when thrown. The distance thrown equals distance fallen for the purposes of determining damage taken. Add 1.5x the throwing creature's strength modifier to damage dealt.
Damaging other creatures - Tiny and Diminuitive creatures do no damage if they hit another being. Small creatures do 1d6 damage per 10ft traveled if they hit another creature, and Medium creatures do 2d6 damager per 10ft traveled.
Thrown creatures that hit another being also perform a bull rush (use the thrower's strength modifier and the thrown creature's size modifier to determine the outcome of the bull rush). The thrown creature must continue with the opponent as it moves."
Here's an illustration: Clayton's got a pipsqueak of a goblin berating him, and it's hard as heck to hit with his hammer. Finally, though, he gives up conventional means of slaughter and is able to grapple it. Now, holding onto it, he wants to make it really pay for all the nasty things it just said to him. He stands 10ft from a cliff and decides it should plummet to its doom. He rolls d20 + his ranged attack bonus - 4 (improvised weapon) - 2 (range increment). The AC in this case is HUGE (wide open spaces). Chances are, he successfully flings the thing to it's doom. It takes the appropriate falling damage and likely dies.
Here's another illustration: That goblin's worg comes after him, and he's got no time to dance with it, for he sees that his friend Amrielle is currently surrounded by a group of goblins by the same cliff. He grapples the puppy normally, then decides to fling it at a goblin in an attempt to knock it off. Clayton is 15 feet from the goblin, who happens to be 10ft from the cliff. He throws the worg, rolling a d20 + his ranged attack bonus - 4 (improvised weapon) - 6 (range increment). If he hits the goblin's touch AC with the attack, the worg deals damage to the goblin, receives damage, and initiates a bull rush versus the goblin.
Clayton get's to represent the worg in the bull rush (it is his attack, after all). He rolls d20 + his strength bonus + 0 (worg size) vs. the goblin's roll. Let's say the worg successfully bull rushes the goblin. If the worg win's by 5 or more, it must choose to follow the goblin and move it further, successfully pushing them both off the cliff.