Can I Play with Madness?
Yes you can, just turn to page 258 of the Dungeon Master's Guide!
Recently I have played with the temporary madness rules to find potentially interesting uses for them. Madness doesn't just have to do with the existential dread that comes with being in Barovia or the Shadowfell, there are other ways to use the d100 table.
The first time I used them I had set up a canyon that the players had to negotiate but in order to make this area noteworthy there were natural stone pillars and on the far side of them grew a psychedelic fungus. As the party were walking into a wind tunnel they were ingesting an ever increasing amount of the toxin. The DC increased in increments of two the closer they got to the end. This was designed to slow down the pace of the session and also make the murder of crows encounter scarier and potentially deadly. As the Fighter was hallucinating the monk had to hold off the swarm while the Bard was babbling incoherently! This led to the Monk feeling good about himself and the others were able to have a fun time roleplaying madness.
The other time I used the madness tables was when I threw these guys at my other party. This was a less serious session and the theme of that story line was to do with a prankster god playing tricks and annoying people for the fun of it! Again this was used as a pacing tool to slow down the party but it was also a clue to the nature of the dungeon and mission that they had been sent on. As more of the party succumbed to the temporary madness of the bagpiping goblins I got to play the music I had cued up on my tablet louder and louder. The relief when the droning instruments were shut off was evident in the room and provided a moment of bonding for the players.
Using the temporary madness table has worked out well for me as it gave me a chance to improvise hallucinations but it also added an element of chance to the situation. Players like dice rolling and the opportunity to roll for negative effects can be exciting.
Give temporary madness a go and may you roll well!