It is always kinda funny to do the more lighthearted ones like the fishbowl routine. One time it helped my friend ease into the trip when he was feeling a bit uneasy. Sure everyone knows it, you pretend your holding an invisible fishbowl, put it around the persons head, before doing so you explain that once you put it on their head they won't be able to hear anything, then once you've placed it on their head, you mouth words instead of saying them aloud, to make it better, pretend to take it off, and once it's "off" their head start speaking normally then slowly place it back on, and mouth your words again. Never had anything go wrong with it and it usually causes a lot of laughs and if the person is gullible enough they'll fall for it. I wouldn't do it to someone on a high dose or anything, and remember to always explain it afterwards so the person doesn't begin to have delusional thoughts or something. Actual pranking is pretty fucked up and annoying, not something I would do.