If we're talking ridiculous to get to then a lot of wizard modes qualify, like on Simpsons, WOZ and LOTR.

If we're talking ridiculous in just what they actually DO... I recently found out what "Barnyard Multiball" is in Medieval Madness... and I pretty much couldn't stop laughing the entire time it was going! XD

I can help you with Barnyard. I've noticed in playing MM in Pinball Arcade that the order the catapult objects appear in is NOT random. In fact, the first five all seem to go in order. (At least, in there. If this can be adjusted on the real machine then this information may or may not help.) So if you want to intentionally go for Barnyard, what you want to do is shoot for the catapult all day and you want to press the flipper buttons to launch items in this manner:

1st Catapult Launch - Hold the flippers before it even starts cycling items.
2nd Catapult Launch - Press the flippers just as you hear the first blip sound.
3rd Catapult Launch - Press the flippers right between the first and second blip sounds.
4th Catapult Launch - Press the flippers just as you hear the second blip sound.
5th Catapult Launch - Press the flippers just as you hear the third blip sound.

That SHOULD get you all five items if your timing is perfect and then it's just one more catapult shot to start Barnyard. Adjust your timing if you're getting repeat items or end up missing one.