[Superfish]

Variant Rule (only tried it once so far, but worked pretty well)
(Works best with Munchkin Cthulhu, but I see no reason why it wouldn't work with any other version)
Munchkin Asylum
You're all Mad!
Using the Madnesses from Cthulhu 2 and 3 create a seperate Deck.
At the beginning of the game each player is dealt one of these madnesses.
The game continues as normal, with the following additional rules:

- Switch Someone's Meds -
Whenever you go up a level on your own turn (the level can be from any source) you may nominate one munchkin (even yourself) to play with their medication. The nominated Munchkin rolls a d6 to determine the results from the following table:

1. Discard all current Madnesses.
2. Discard 1 Madness (your choice) and draw another.
3. Swap any Madness(es) with those of the player to your left.
4. Swap any Madness(es) with those of the player to your right.
5. Swap any Madness(es) with those of the player who nominated you.
6. Draw another Madness.

You may nominate one Munchkin per level you earn and may nominate the same Munchkin twice in one turn, resolving each die roll before making the next.

-The Well of Madness is Never Dry -
Discarded Madnesses go back into the Madness Deck. If at any time you are asked to draw the last Madness in the deck then you Must replace the drawn madness with one of your current Madnesses. If you cannot then the player(s) with the most Madnesses must discard 1 (each). (Not sure about this rule, still looking for a good way to stop the well of madness running dry)

Wishing Rings and Sudden Head Blows still act as normal, as well as any Monster effects/Bad Stuff which affect Madnesses

Please test this and tell me what you think :)