Here’s something that just hit me:
1. Each player brings their own unique set of “adventure game” dice, d4 to d20.
2. Roll a whole bunch of other random dice on the table, like the “scoop-worth” you can buy from Chessex at conventions.
3. Take turns doing the following:
A. Starting with your d4, roll your die onto the playing space, trying to get it to touch a bunch of other dice. You’re going to want to do this strategically, as you’ll see in a minute.
B. Pick up your die and whatever dice are touching it. Roll these together separately off to the side.
C. If your dice rolls higher than some of the other dice, SUCCESS! You’ve captured them! Place them in your personal stash, away from the play space, and return the others to the central pool, just rolling them back onto the table.
D. Pass the turn to the next player and, while they’re going, roll your dice on MASSIVE TABLE NOT INCLUDED to figure out what you captured. This table is subdivided by your current die size, so start with the d4 tables. Maybe you captured a thumbtack or a pack of chewing gum!
E. If you’ve collected objects equal to the faces on your current die, CONGRATULATIONS! You’ve increased your die size! On your next turn, roll the die from your set that’s one step bigger: d4 > d6 > d8 > d10 > d12 > d20.
4. You win the game if you expand your rolling die past d20 (rolling up 20 dice with a d20) or if you have the largest collection of stuff when all the dice are removed from the table (or, whenever you decide to stop).
5. It is recommended that, whenever they roll, players are required to hum or sing the themesong to Katamari Damacy.
6. There are SECRET BONUS rules for what happens when you get a bunch of the same thing (i.e. multiple cows) or complementary items (toothbrush and toothpaste).