When I was attending Simon's Rock College in western Massachusetts, one of our favorite pastimes was sitting in our rooms in Kendrick stereotypically getting stoned. Another of our favorite pastimes was playing the venerated dice game Cosmic Wimpout. Under the influence of a moment of clarity, once upon a time we combined these two activities into the game Cosmic Bongout. We thought of ourselves as pioneers, but later in my life, living in Athens, Georgia, I discovered an enclave of people who enjoyed the very same pastime. I can only imagine that its parallel development has occurred throughout the nation, a testament to the power of the collective subconscious. Or maybe it's just that people like to get stoned. At any rate, the standard rules of Cosmic Wimpout apply, but with a few modifications.
For every 100 points you accumulate, you must take one bong hit. This only applies at the end of a turn, after you Opt to Stop, when the points become permanent and are added to your score. However, you only get to take a hit the first time you reach that milestone. So if you're playing with The Boot rule, and you score 250 points, then later get Booted back down to 80, you do not earn another hit upon reaching 100 and 200 points the second time. You also get an additional hit every time you roll a Freight Train (five matching dice), or when you win the game. These are cumulative with, and independent of, any hits you earn purely as a result of points. So following the above example, if at 80 points you rolled a Freight Train of twos, you would still get a bong hit for the Freight Train even though you would not get a bong hit for passing 100 and 200 points.
Bong hits must be taken when they are earned. There are no exceptions. If a player is caught cheating - that is, altering his dice or his score so as to achieve an extra bong hit (or, God forbid, to avoid one) - he is cursed. Whenever a cursed player earns a bong hit, all the other players roll dice, and the highest roll must take the cursed player's hit. Bummer for them.
Any player who commits substance abuse (that is, abuses the substance) is penalized 100 points. This might include spilling the bong water, dumping out the weed, volcano-ing the bowl, and so forth. Repeated offenses may result in cursing (see above).
When I played this game in Athens, they had developed a Challenge rule. If a player fell victim to the You May Not Want To But You Must rule, any other player might Challenge them at any time after that. Following a Challenge, if the challenged player rolled and did not Wimpout on that roll, that player had to take another hit. If they did Wimpout on that roll, the challenger had to take a hit. I think this was basically because the people I hung out with in Athens felt that basic Cosmic Bongout didn't offer enough chances to take bong hits. Good folk down there.
Tips: For the sake of expedition, it is best not to use a bong with a one-hit bowl (that involves lots of packing and re-packing in certain situations). If you don't have a bong, and you're going to use joints, make sure you have a few rolled ahead of time. You can also play Cosmic Bongout as a drinking game if you don't have any weed, although be warned that it's really not quite as fun. There is also another variant of this game played in the Southeast USA called Zonk, but it's more like Yahtzee than Cosmic Wimpout.