Seek altered space (And not just the chemical sort). Crack an unusual book. Read a book backwards.
Challenge your assumptions. Challenge your worldview; break it down everything you've ever known or assumed or taken as fact and chuck it flaming from the nearest window.
Experience something unusual. Throw yourself into situations that may be life threatening, if not only strange and totally without prior context or subtext. Make music out of anything; DJ with your toaster, your washer, your bicycle, your shoes.
Develop and experiment with strange fetishes; Make a fetish of or make fetishes of uncommon things. Sexualize a tree, a rock, a blade of grass, a pile of excrement, a housefly. View flowers and fruit as sexual organs and then fantasize about them. Masturbate with something unusual. Insert strange objects into various holes in your body. Make new holes in your body. Experience real physical pain and turn it into pleasure with the power of your mind. Have a good friend or lover expose you to unusual textures or sensations.
Practice personal and interpersonal celibacy to the verge of insanity, then masturbate or copulate to orgasm as many times as possible in a 24 hour period. Use methods of physical restraint like locking/binding/restraint devices, or physical barriers like plaster
casts if desired. Then push yourself into a rictus of transcendental hedonism, push yourself through any preconceived barriers of orgiastic limitations.
Wear your lover's clothes. Wear no clothes. Go about your normal public day in something you would never normally wear. Convince a perfect stranger to trade clothes with you in public. Invent an elaborate, functional costume for an unearthly fictional character, complete with fictional religion, taboos, habits, tools, beliefs and artifacts. Bonus points for invented languages and literature - especially if they bear no resemblance at all to any form of written or spoken earthly language.
Try new foods. Try new foods with other new foods mixed together in entirely improbable combinations. Eat the inedible. Taste your own excrement. Taste your own blood.
Make a silicon mold of your face or genitals, then cook a very realistic jello salad in it, and then eat it.
Challenge a complete stranger to a pointless argument. Take the opposite side in the argument that you would normally.
Spend the day "blind", blindfolding yourself. Spend the day "deaf" and keep the strongest earplugs that you can find all day. Hold a mirror under your nose and pretend to walk around the house on the ceiling, then step outside into the open sky. Put your shoes on the wrong feet. Put your underwear on backwards. Talk to bugs. Spend the day as one.
Invent and practice strange rituals or meditations that have meaning to no one but yourself. Fingerpaint. On your body. With pudding. Light something on fire. Light something meaningful to you on fire. Light a candle and then attempt to eat it. Take a long walk somewhere you've never been before. Ride the bus, subway, or train somewhere you've never been before. Walk into a traditional and fine restaurant of a completely alien and foreign ethnicity and ask for the house special. Get drunk with someone that doesn't speak your language. Refrain from linguistically/symbolically communicating for an hour, a week, a month.
Take a twenty-pound sledgehammer and vigorously and fanatically wield it against your confining ten-pound mold, your five-pound rut and smash the ever loving shit out of it, lovingly.