Birthday of a marijuana smoker would be like:
20 guests coming to a birthday party. Guests presenting to a birthday boy the presents like: t-shirt with marijuana leaf, ounce of weed, pipe, bong, etc. Everybody sitting for the table with snacks, and each guest does having clean bong or pipe as his private dishes (by principle of small glass to drink vodka on a party). Some guest does saying a congratulation, while holding in his hand a bong. And after he says "cheers", all together do smoking marijuana from the personal bong or pipe.